Merge remote-tracking branch 'origin/5.14' into 5.15

Change-Id: Ibe5b4aa249863a54007180f3684dc5ce1b23cb7b

28 files changed, 489 insertions, 298 deletions

diff --git a/src/3rdparty/md4c/md4c.c b/src/3rdparty/md4c/md4c.c
index 3745cf3e46..b0ef739b3c 100644
--- a/src/3rdparty/md4c/md4c.c
+++ b/src/3rdparty/md4c/md4c.c
@@ -2,7 +2,7 @@
  * MD4C: Markdown parser for C
  * (http://github.com/mity/md4c)
  *
- * Copyright (c) 2016-2019 Martin Mitas
+ * Copyright (c) 2016-2020 Martin Mitas
  *
  * Permission is hereby granted, free of charge, to any person obtaining a
  * copy of this software and associated documentation files (the "Software"),
@@ -35,14 +35,23 @@
  ***  Miscellaneous Stuff  ***
  *****************************/
 
-#ifdef _MSC_VER
-    /* MSVC does not understand "inline" when building as pure C (not C++).
-     * However it understands "__inline" */
-    #ifndef __cplusplus
+#if !defined(__STDC_VERSION__) || __STDC_VERSION__ < 199409L
+    /* C89/90 or old compilers in general may not understand "inline". */
+    #if defined __GNUC__
+        #define inline __inline__
+    #elif defined _MSC_VER
         #define inline __inline
+    #else
+        #define inline
     #endif
 #endif
 
+/* Make the UTF-8 support the default. */
+#if !defined MD4C_USE_ASCII && !defined MD4C_USE_UTF8 && !defined MD4C_USE_UTF16
+    #define MD4C_USE_UTF8
+#endif
+
+/* Magic for making wide literals with MD4C_USE_UTF16. */
 #ifdef _T
     #undef _T
 #endif
@@ -127,7 +136,7 @@ struct MD_CTX_tag {
 #endif
 
     /* For resolving of inline spans. */
-    MD_MARKCHAIN mark_chains[12];
+    MD_MARKCHAIN mark_chains[13];
 #define PTR_CHAIN                               ctx->mark_chains[0]
 #define TABLECELLBOUNDARIES                     ctx->mark_chains[1]
 #define ASTERISK_OPENERS_extraword_mod3_0       ctx->mark_chains[2]
@@ -137,11 +146,12 @@ struct MD_CTX_tag {
 #define ASTERISK_OPENERS_intraword_mod3_1       ctx->mark_chains[6]
 #define ASTERISK_OPENERS_intraword_mod3_2       ctx->mark_chains[7]
 #define UNDERSCORE_OPENERS                      ctx->mark_chains[8]
-#define TILDE_OPENERS                           ctx->mark_chains[9]
-#define BRACKET_OPENERS                         ctx->mark_chains[10]
-#define DOLLAR_OPENERS                          ctx->mark_chains[11]
+#define TILDE_OPENERS_1                         ctx->mark_chains[9]
+#define TILDE_OPENERS_2                         ctx->mark_chains[10]
+#define BRACKET_OPENERS                         ctx->mark_chains[11]
+#define DOLLAR_OPENERS                          ctx->mark_chains[12]
 #define OPENERS_CHAIN_FIRST                     2
-#define OPENERS_CHAIN_LAST                      11
+#define OPENERS_CHAIN_LAST                      12
 
     int n_table_cell_boundaries;
 
@@ -263,6 +273,9 @@ struct MD_VERBATIMLINE_tag {
 #define CH(off)                 (ctx->text[(off)])
 #define STR(off)                (ctx->text + (off))
 
+/* Check whether the pointer points into ctx->text. */
+#define IS_INPUT_STR(ptr)       (ctx->text <= (ptr)  &&  (ptr) < (ctx->text + ctx->size))
+
 /* Character classification.
  * Note we assume ASCII compatibility of code points < 128 here. */
 #define ISIN_(ch, ch_min, ch_max)       ((ch_min) <= (unsigned)(ch) && (unsigned)(ch) <= (ch_max))
@@ -297,16 +310,14 @@ struct MD_VERBATIMLINE_tag {
 #define ISDIGIT(off)                    ISDIGIT_(CH(off))
 #define ISXDIGIT(off)                   ISXDIGIT_(CH(off))
 #define ISALNUM(off)                    ISALNUM_(CH(off))
-static inline const CHAR*
-md_strchr(const CHAR* str, CHAR ch)
-{
-    OFF i;
-    for(i = 0; str[i] != _T('\0'); i++) {
-        if(ch == str[i])
-            return (str + i);
-    }
-    return NULL;
-}
+
+
+#if defined MD4C_USE_UTF16
+    #define md_strchr wcschr
+#else
+    #define md_strchr strchr
+#endif
+
 
 /* Case insensitive check of string equality. */
 static inline int
@@ -364,89 +375,89 @@ md_text_with_null_replacement(MD_CTX* ctx, MD_TEXTTYPE type, const CHAR* str, SZ
 }
 
 
-#define MD_CHECK(func)                                                  \
-    do {                                                                \
-        ret = (func);                                                   \
-        if(ret < 0)                                                     \
-            goto abort;                                                 \
+#define MD_CHECK(func)                                                      \
+    do {                                                                    \
+        ret = (func);                                                       \
+        if(ret < 0)                                                         \
+            goto abort;                                                     \
     } while(0)
 
 
-#define MD_TEMP_BUFFER(sz)                                              \
-    do {                                                                \
-        if(sz > ctx->alloc_buffer) {                                    \
-            CHAR* new_buffer;                                           \
-            SZ new_size = ((sz) + (sz) / 2 + 128) & ~127;               \
-                                                                        \
-            new_buffer = realloc(ctx->buffer, new_size);                \
-            if(new_buffer == NULL) {                                    \
-                MD_LOG("realloc() failed.");                            \
-                ret = -1;                                               \
-                goto abort;                                             \
-            }                                                           \
-                                                                        \
-            ctx->buffer = new_buffer;                                   \
-            ctx->alloc_buffer = new_size;                               \
-        }                                                               \
+#define MD_TEMP_BUFFER(sz)                                                  \
+    do {                                                                    \
+        if(sz > ctx->alloc_buffer) {                                        \
+            CHAR* new_buffer;                                               \
+            SZ new_size = ((sz) + (sz) / 2 + 128) & ~127;                   \
+                                                                            \
+            new_buffer = realloc(ctx->buffer, new_size);                    \
+            if(new_buffer == NULL) {                                        \
+                MD_LOG("realloc() failed.");                                \
+                ret = -1;                                                   \
+                goto abort;                                                 \
+            }                                                               \
+                                                                            \
+            ctx->buffer = new_buffer;                                       \
+            ctx->alloc_buffer = new_size;                                   \
+        }                                                                   \
     } while(0)
 
 
-#define MD_ENTER_BLOCK(type, arg)                                       \
-    do {                                                                \
-        ret = ctx->parser.enter_block((type), (arg), ctx->userdata);         \
-        if(ret != 0) {                                                  \
-            MD_LOG("Aborted from enter_block() callback.");             \
-            goto abort;                                                 \
-        }                                                               \
+#define MD_ENTER_BLOCK(type, arg)                                           \
+    do {                                                                    \
+        ret = ctx->parser.enter_block((type), (arg), ctx->userdata);        \
+        if(ret != 0) {                                                      \
+            MD_LOG("Aborted from enter_block() callback.");                 \
+            goto abort;                                                     \
+        }                                                                   \
     } while(0)
 
-#define MD_LEAVE_BLOCK(type, arg)                                       \
-    do {                                                                \
-        ret = ctx->parser.leave_block((type), (arg), ctx->userdata);         \
-        if(ret != 0) {                                                  \
-            MD_LOG("Aborted from leave_block() callback.");             \
-            goto abort;                                                 \
-        }                                                               \
+#define MD_LEAVE_BLOCK(type, arg)                                           \
+    do {                                                                    \
+        ret = ctx->parser.leave_block((type), (arg), ctx->userdata);        \
+        if(ret != 0) {                                                      \
+            MD_LOG("Aborted from leave_block() callback.");                 \
+            goto abort;                                                     \
+        }                                                                   \
     } while(0)
 
-#define MD_ENTER_SPAN(type, arg)                                        \
-    do {                                                                \
-        ret = ctx->parser.enter_span((type), (arg), ctx->userdata);          \
-        if(ret != 0) {                                                  \
-            MD_LOG("Aborted from enter_span() callback.");              \
-            goto abort;                                                 \
-        }                                                               \
+#define MD_ENTER_SPAN(type, arg)                                            \
+    do {                                                                    \
+        ret = ctx->parser.enter_span((type), (arg), ctx->userdata);         \
+        if(ret != 0) {                                                      \
+            MD_LOG("Aborted from enter_span() callback.");                  \
+            goto abort;                                                     \
+        }                                                                   \
     } while(0)
 
-#define MD_LEAVE_SPAN(type, arg)                                        \
-    do {                                                                \
-        ret = ctx->parser.leave_span((type), (arg), ctx->userdata);          \
-        if(ret != 0) {                                                  \
-            MD_LOG("Aborted from leave_span() callback.");              \
-            goto abort;                                                 \
-        }                                                               \
+#define MD_LEAVE_SPAN(type, arg)                                            \
+    do {                                                                    \
+        ret = ctx->parser.leave_span((type), (arg), ctx->userdata);         \
+        if(ret != 0) {                                                      \
+            MD_LOG("Aborted from leave_span() callback.");                  \
+            goto abort;                                                     \
+        }                                                                   \
     } while(0)
 
-#define MD_TEXT(type, str, size)                                        \
-    do {                                                                \
-        if(size > 0) {                                                  \
-            ret = ctx->parser.text((type), (str), (size), ctx->userdata);    \
-            if(ret != 0) {                                              \
-                MD_LOG("Aborted from text() callback.");                \
-                goto abort;                                             \
-            }                                                           \
-        }                                                               \
+#define MD_TEXT(type, str, size)                                            \
+    do {                                                                    \
+        if(size > 0) {                                                      \
+            ret = ctx->parser.text((type), (str), (size), ctx->userdata);   \
+            if(ret != 0) {                                                  \
+                MD_LOG("Aborted from text() callback.");                    \
+                goto abort;                                                 \
+            }                                                               \
+        }                                                                   \
     } while(0)
 
-#define MD_TEXT_INSECURE(type, str, size)                               \
-    do {                                                                \
-        if(size > 0) {                                                  \
-            ret = md_text_with_null_replacement(ctx, type, str, size);  \
-            if(ret != 0) {                                              \
-                MD_LOG("Aborted from text() callback.");                \
-                goto abort;                                             \
-            }                                                           \
-        }                                                               \
+#define MD_TEXT_INSECURE(type, str, size)                                   \
+    do {                                                                    \
+        if(size > 0) {                                                      \
+            ret = md_text_with_null_replacement(ctx, type, str, size);      \
+            if(ret != 0) {                                                  \
+                MD_LOG("Aborted from text() callback.");                    \
+                goto abort;                                                 \
+            }                                                               \
+        }                                                                   \
     } while(0)
 
 
@@ -1329,8 +1340,9 @@ md_build_attr_append_substr(MD_CTX* ctx, MD_ATTRIBUTE_BUILD* build,
         MD_TEXTTYPE* new_substr_types;
         OFF* new_substr_offsets;
 
-        build->substr_alloc = (build->substr_alloc == 0 ? 8 : build->substr_alloc * 2);
-
+        build->substr_alloc = (build->substr_alloc > 0
+                ? build->substr_alloc + build->substr_alloc / 2
+                : 8);
         new_substr_types = (MD_TEXTTYPE*) realloc(build->substr_types,
                                     build->substr_alloc * sizeof(MD_TEXTTYPE));
         if(new_substr_types == NULL) {
@@ -1456,8 +1468,8 @@ abort:
  ***  Dictionary of Reference Definitions  ***
  *********************************************/
 
-#define MD_FNV1A_BASE       2166136261
-#define MD_FNV1A_PRIME      16777619
+#define MD_FNV1A_BASE       2166136261U
+#define MD_FNV1A_PRIME      16777619U
 
 static inline unsigned
 md_fnv1a(unsigned base, const void* data, size_t n)
@@ -1479,9 +1491,7 @@ struct MD_REF_DEF_tag {
     CHAR* label;
     CHAR* title;
     unsigned hash;
-    SZ label_size                   : 24;
-    unsigned label_needs_free       :  1;
-    unsigned title_needs_free       :  1;
+    SZ label_size;
     SZ title_size;
     OFF dest_beg;
     OFF dest_end;
@@ -1530,7 +1540,7 @@ md_link_label_cmp_load_fold_info(const CHAR* label, OFF off, SZ size,
     SZ char_size;
 
     if(off >= size) {
-        /* Treat end of link label as a whitespace. */
+        /* Treat end of a link label as a whitespace. */
         goto whitespace;
     }
 
@@ -1554,7 +1564,7 @@ md_link_label_cmp_load_fold_info(const CHAR* label, OFF off, SZ size,
 whitespace:
     fold_info->codepoints[0] = _T(' ');
     fold_info->n_codepoints = 1;
-    return off;
+    return md_skip_unicode_whitespace(label, off, size);
 }
 
 static int
@@ -1572,7 +1582,7 @@ md_link_label_cmp(const CHAR* a_label, SZ a_size, const CHAR* b_label, SZ b_size
 
     a_off = md_skip_unicode_whitespace(a_label, 0, a_size);
     b_off = md_skip_unicode_whitespace(b_label, 0, b_size);
-    while(!a_reached_end  &&  !b_reached_end) {
+    while(!a_reached_end  ||  !b_reached_end) {
         /* If needed, load fold info for next char. */
         if(a_fi_off >= a_fi.n_codepoints) {
             a_fi_off = 0;
@@ -1618,7 +1628,7 @@ md_ref_def_cmp(const void* a, const void* b)
 }
 
 static int
-md_ref_def_cmp_stable(const void* a, const void* b)
+md_ref_def_cmp_for_sort(const void* a, const void* b)
 {
     int cmp;
 
@@ -1671,6 +1681,7 @@ md_build_ref_def_hashtable(MD_CTX* ctx)
         bucket = ctx->ref_def_hashtable[def->hash % ctx->ref_def_hashtable_size];
 
         if(bucket == NULL) {
+            /* The bucket is empty. Make it just point to the def. */
             ctx->ref_def_hashtable[def->hash % ctx->ref_def_hashtable_size] = def;
             continue;
         }
@@ -1682,12 +1693,12 @@ md_build_ref_def_hashtable(MD_CTX* ctx)
             MD_REF_DEF* old_def = (MD_REF_DEF*) bucket;
 
             if(md_link_label_cmp(def->label, def->label_size, old_def->label, old_def->label_size) == 0) {
-                /* Ignore this ref. def. */
+                /* Duplicate label: Ignore this ref. def. */
                 continue;
             }
 
-            /* Make the bucket capable of holding more ref. defs. */
-            list = (MD_REF_DEF_LIST*) malloc(sizeof(MD_REF_DEF_LIST) + 4 * sizeof(MD_REF_DEF*));
+            /* Make the bucket complex, i.e. able to hold more ref. defs. */
+            list = (MD_REF_DEF_LIST*) malloc(sizeof(MD_REF_DEF_LIST) + 2 * sizeof(MD_REF_DEF*));
             if(list == NULL) {
                 MD_LOG("malloc() failed.");
                 goto abort;
@@ -1695,22 +1706,28 @@ md_build_ref_def_hashtable(MD_CTX* ctx)
             list->ref_defs[0] = old_def;
             list->ref_defs[1] = def;
             list->n_ref_defs = 2;
-            list->alloc_ref_defs = 4;
+            list->alloc_ref_defs = 2;
             ctx->ref_def_hashtable[def->hash % ctx->ref_def_hashtable_size] = list;
             continue;
         }
 
-        /* Append the def to the bucket list. */
+        /* Append the def to the complex bucket list.
+         *
+         * Note in this case we ignore potential duplicates to avoid expensive
+         * iterating over the complex bucket. Below, we revisit all the complex
+         * buckets and handle it more cheaply after the complex bucket contents
+         * is sorted. */
         list = (MD_REF_DEF_LIST*) bucket;
         if(list->n_ref_defs >= list->alloc_ref_defs) {
+            int alloc_ref_defs = list->alloc_ref_defs + list->alloc_ref_defs / 2;
             MD_REF_DEF_LIST* list_tmp = (MD_REF_DEF_LIST*) realloc(list,
-                        sizeof(MD_REF_DEF_LIST) + 2 * list->alloc_ref_defs * sizeof(MD_REF_DEF*));
+                        sizeof(MD_REF_DEF_LIST) + alloc_ref_defs * sizeof(MD_REF_DEF*));
             if(list_tmp == NULL) {
                 MD_LOG("realloc() failed.");
                 goto abort;
             }
             list = list_tmp;
-            list->alloc_ref_defs *= 2;
+            list->alloc_ref_defs = alloc_ref_defs;
             ctx->ref_def_hashtable[def->hash % ctx->ref_def_hashtable_size] = list;
         }
 
@@ -1729,9 +1746,12 @@ md_build_ref_def_hashtable(MD_CTX* ctx)
             continue;
 
         list = (MD_REF_DEF_LIST*) bucket;
-        qsort(list->ref_defs, list->n_ref_defs, sizeof(MD_REF_DEF*), md_ref_def_cmp_stable);
+        qsort(list->ref_defs, list->n_ref_defs, sizeof(MD_REF_DEF*), md_ref_def_cmp_for_sort);
 
-        /* Disable duplicates. */
+        /* Disable all duplicates in the complex bucket by forcing all such
+         * records to point to the 1st such ref. def. I.e. no matter which
+         * record is found during the lookup, it will always point to the right
+         * ref. def. in ctx->ref_defs[]. */
         for(j = 1; j < list->n_ref_defs; j++) {
             if(md_ref_def_cmp(&list->ref_defs[j-1], &list->ref_defs[j]) == 0)
                 list->ref_defs[j] = list->ref_defs[j-1];
@@ -2055,9 +2075,8 @@ md_is_link_reference_definition(MD_CTX* ctx, const MD_LINE* lines, int n_lines)
     OFF label_contents_end;
     int label_contents_line_index = -1;
     int label_is_multiline;
-    CHAR* label;
+    CHAR* label = NULL;
     SZ label_size;
-    int label_needs_free = FALSE;
     OFF dest_contents_beg;
     OFF dest_contents_end;
     OFF title_contents_beg;
@@ -2123,23 +2142,22 @@ md_is_link_reference_definition(MD_CTX* ctx, const MD_LINE* lines, int n_lines)
     if(!label_is_multiline) {
         label = (CHAR*) STR(label_contents_beg);
         label_size = label_contents_end - label_contents_beg;
-        label_needs_free = FALSE;
     } else {
         MD_CHECK(md_merge_lines_alloc(ctx, label_contents_beg, label_contents_end,
                     lines + label_contents_line_index, n_lines - label_contents_line_index,
                     _T(' '), &label, &label_size));
-        label_needs_free = TRUE;
     }
 
     /* Store the reference definition. */
     if(ctx->n_ref_defs >= ctx->alloc_ref_defs) {
         MD_REF_DEF* new_defs;
 
-        ctx->alloc_ref_defs = (ctx->alloc_ref_defs > 0 ? ctx->alloc_ref_defs * 2 : 16);
+        ctx->alloc_ref_defs = (ctx->alloc_ref_defs > 0
+                ? ctx->alloc_ref_defs + ctx->alloc_ref_defs / 2
+                : 16);
         new_defs = (MD_REF_DEF*) realloc(ctx->ref_defs, ctx->alloc_ref_defs * sizeof(MD_REF_DEF));
         if(new_defs == NULL) {
             MD_LOG("realloc() failed.");
-            ret = -1;
             goto abort;
         }
 
@@ -2151,7 +2169,6 @@ md_is_link_reference_definition(MD_CTX* ctx, const MD_LINE* lines, int n_lines)
 
     def->label = label;
     def->label_size = label_size;
-    def->label_needs_free = label_needs_free;
 
     def->dest_beg = dest_contents_beg;
     def->dest_end = dest_contents_end;
@@ -2166,7 +2183,6 @@ md_is_link_reference_definition(MD_CTX* ctx, const MD_LINE* lines, int n_lines)
         MD_CHECK(md_merge_lines_alloc(ctx, title_contents_beg, title_contents_end,
                     lines + title_contents_line_index, n_lines - title_contents_line_index,
                     _T('\n'), &def->title, &def->title_size));
-        def->title_needs_free = TRUE;
     }
 
     /* Success. */
@@ -2175,9 +2191,9 @@ md_is_link_reference_definition(MD_CTX* ctx, const MD_LINE* lines, int n_lines)
 
 abort:
     /* Failure. */
-    if(label_needs_free)
+    if(!IS_INPUT_STR(label))
         free(label);
-    return -1;
+    return ret;
 }
 
 static int
@@ -2225,7 +2241,7 @@ md_is_link_reference(MD_CTX* ctx, const MD_LINE* lines, int n_lines,
         attr->title_needs_free = FALSE;
     }
 
-    if(beg_line != end_line)
+    if(!IS_INPUT_STR(label))
         free(label);
 
     ret = (def != NULL);
@@ -2339,9 +2355,9 @@ md_free_ref_defs(MD_CTX* ctx)
     for(i = 0; i < ctx->n_ref_defs; i++) {
         MD_REF_DEF* def = &ctx->ref_defs[i];
 
-        if(def->label_needs_free)
+        if(!IS_INPUT_STR(def->label))
             free(def->label);
-        if(def->title_needs_free)
+        if(!IS_INPUT_STR(def->title))
             free(def->title);
     }
 
@@ -2470,7 +2486,7 @@ md_mark_chain(MD_CTX* ctx, int mark_index)
     switch(mark->ch) {
         case _T('*'):   return md_asterisk_chain(ctx, mark->flags);
         case _T('_'):   return &UNDERSCORE_OPENERS;
-        case _T('~'):   return &TILDE_OPENERS;
+        case _T('~'):   return (mark->end - mark->beg == 1) ? &TILDE_OPENERS_1 : &TILDE_OPENERS_2;
         case _T('['):   return &BRACKET_OPENERS;
         case _T('|'):   return &TABLECELLBOUNDARIES;
         default:        return NULL;
@@ -2483,7 +2499,9 @@ md_push_mark(MD_CTX* ctx)
     if(ctx->n_marks >= ctx->alloc_marks) {
         MD_MARK* new_marks;
 
-        ctx->alloc_marks = (ctx->alloc_marks > 0 ? ctx->alloc_marks * 2 : 64);
+        ctx->alloc_marks = (ctx->alloc_marks > 0
+                ? ctx->alloc_marks + ctx->alloc_marks / 2
+                : 64);
         new_marks = realloc(ctx->marks, ctx->alloc_marks * sizeof(MD_MARK));
         if(new_marks == NULL) {
             MD_LOG("realloc() failed.");
@@ -2526,6 +2544,7 @@ md_mark_chain_append(MD_CTX* ctx, MD_MARKCHAIN* chain, int mark_index)
         chain->head = mark_index;
 
     ctx->marks[mark_index].prev = chain->tail;
+    ctx->marks[mark_index].next = -1;
     chain->tail = mark_index;
 }
 
@@ -2617,7 +2636,7 @@ md_rollback(MD_CTX* ctx, int opener_index, int closer_index, int how)
             chain->head = -1;
     }
 
-    /* Go backwards so that un-resolved openers are re-added into their
+    /* Go backwards so that unresolved openers are re-added into their
      * respective chains, in the right order. */
     mark_index = closer_index - 1;
     while(mark_index > opener_index) {
@@ -2696,7 +2715,7 @@ md_build_mark_char_map(MD_CTX* ctx)
     if(ctx->parser.flags & MD_FLAG_PERMISSIVEWWWAUTOLINKS)
         ctx->mark_char_map['.'] = 1;
 
-    if(ctx->parser.flags & MD_FLAG_TABLES)
+    if((ctx->parser.flags & MD_FLAG_TABLES) || (ctx->parser.flags & MD_FLAG_WIKILINKS))
         ctx->mark_char_map['|'] = 1;
 
     if(ctx->parser.flags & MD_FLAG_COLLAPSEWHITESPACE) {
@@ -2896,7 +2915,7 @@ md_is_autolink_email(MD_CTX* ctx, OFF beg, OFF max_end, OFF* p_end)
         return FALSE;
     off++;
 
-    /* Labels delimited with '.'; each label is sequence of 1 - 62 alnum
+    /* Labels delimited with '.'; each label is sequence of 1 - 63 alnum
      * characters or '-', but '-' is not allowed as first or last char. */
     label_len = 0;
     while(off < max_end) {
@@ -2909,7 +2928,7 @@ md_is_autolink_email(MD_CTX* ctx, OFF beg, OFF max_end, OFF* p_end)
         else
             break;
 
-        if(label_len > 62)
+        if(label_len > 63)
             return FALSE;
 
         off++;
@@ -3236,8 +3255,8 @@ md_collect_marks(MD_CTX* ctx, const MD_LINE* lines, int n_lines, int table_mode)
                 continue;
             }
 
-            /* A potential table cell boundary. */
-            if(table_mode  &&  ch == _T('|')) {
+            /* A potential table cell boundary or wiki link label delimiter. */
+            if((table_mode || ctx->parser.flags & MD_FLAG_WIKILINKS) && ch == _T('|')) {
                 PUSH_MARK(ch, off, off+1, 0);
                 off++;
                 continue;
@@ -3250,7 +3269,17 @@ md_collect_marks(MD_CTX* ctx, const MD_LINE* lines, int n_lines, int table_mode)
                 while(tmp < line_end  &&  CH(tmp) == _T('~'))
                     tmp++;
 
-                PUSH_MARK(ch, off, tmp, MD_MARK_POTENTIAL_OPENER | MD_MARK_POTENTIAL_CLOSER);
+                if(tmp - off < 3) {
+                    unsigned flags = 0;
+
+                    if(tmp < line_end  &&  !ISUNICODEWHITESPACE(tmp))
+                        flags |= MD_MARK_POTENTIAL_OPENER;
+                    if(off > line->beg  &&  !ISUNICODEWHITESPACEBEFORE(off))
+                        flags |= MD_MARK_POTENTIAL_CLOSER;
+                    if(flags != 0)
+                        PUSH_MARK(ch, off, tmp, flags);
+                }
+
                 off = tmp;
                 continue;
             }
@@ -3398,6 +3427,91 @@ md_resolve_links(MD_CTX* ctx, const MD_LINE* lines, int n_lines)
             continue;
         }
 
+        /* Recognize and resolve wiki links.
+         * Wiki-links maybe '[[destination]]' or '[[destination|label]]'.
+         */
+        if ((ctx->parser.flags & MD_FLAG_WIKILINKS) &&
+            (opener->end - opener->beg == 1) &&         /* not image */
+            next_opener != NULL &&                      /* double '[' opener */
+            next_opener->ch == '[' &&
+            (next_opener->beg == opener->beg - 1) &&
+            (next_opener->end - next_opener->beg == 1) &&
+            next_closer != NULL &&                      /* double ']' closer */
+            next_closer->ch == ']' &&
+            (next_closer->beg == closer->beg + 1) &&
+            (next_closer->end - next_closer->beg == 1))
+        {
+            MD_MARK* delim = NULL;
+            int delim_index;
+            OFF dest_beg, dest_end;
+
+            is_link = TRUE;
+
+            /* We don't allow destination to be longer then 100 characters.
+             * Lets scan to see whether there is '|'. (If not then the whole
+             * wiki-link has to be below the 100 characters.) */
+            delim_index = opener_index + 1;
+            while(delim_index < closer_index) {
+                MD_MARK* m = &ctx->marks[delim_index];
+                if(m->ch == '|') {
+                    delim = m;
+                    break;
+                }
+                if(m->ch != 'D'  &&  m->beg - opener->end > 100)
+                    break;
+                delim_index++;
+            }
+            dest_beg = opener->end;
+            dest_end = (delim != NULL) ? delim->beg : closer->beg;
+            if(dest_end - dest_beg == 0 || dest_end - dest_beg > 100)
+                is_link = FALSE;
+
+            /* There may not be any new line in the destination. */
+            if(is_link) {
+                OFF off;
+                for(off = dest_beg; off < dest_end; off++) {
+                    if(ISNEWLINE(off)) {
+                        is_link = FALSE;
+                        break;
+                    }
+                }
+            }
+
+            if(is_link) {
+                if(delim != NULL) {
+                    if(delim->end < closer->beg) {
+                        opener->end = delim->beg;
+                    } else {
+                        /* The pipe is just before the closer: [[foo|]] */
+                        closer->beg = delim->beg;
+                        delim = NULL;
+                    }
+                }
+
+                opener->beg = next_opener->beg;
+                opener->next = closer_index;
+                opener->flags |= MD_MARK_OPENER | MD_MARK_RESOLVED;
+
+                closer->end = next_closer->end;
+                closer->prev = opener_index;
+                closer->flags |= MD_MARK_CLOSER | MD_MARK_RESOLVED;
+
+                last_link_beg = opener->beg;
+                last_link_end = closer->end;
+
+                if(delim != NULL) {
+                    delim->flags |= MD_MARK_RESOLVED;
+                    md_rollback(ctx, opener_index, delim_index, MD_ROLLBACK_ALL);
+                    md_analyze_link_contents(ctx, lines, n_lines, opener_index+1, closer_index);
+                } else {
+                    md_rollback(ctx, opener_index, closer_index, MD_ROLLBACK_ALL);
+                }
+
+                opener_index = next_opener->prev;
+                continue;
+            }
+        }
+
         if(next_opener != NULL  &&  next_opener->beg == closer->end) {
             if(next_closer->beg > closer->end + 1) {
                 /* Might be full reference link. */
@@ -3436,7 +3550,7 @@ md_resolve_links(MD_CTX* ctx, const MD_LINE* lines, int n_lines)
                         if((mark->flags & (MD_MARK_OPENER | MD_MARK_RESOLVED)) == (MD_MARK_OPENER | MD_MARK_RESOLVED)) {
                             if(ctx->marks[mark->next].beg >= inline_link_end) {
                                 /* Cancel the link status. */
-                                if(attr.title_needs_free)
+                                if(!IS_INPUT_STR(attr.title))
                                     free(attr.title);
                                 is_link = FALSE;
                                 break;
@@ -3476,6 +3590,7 @@ md_resolve_links(MD_CTX* ctx, const MD_LINE* lines, int n_lines)
 
             MD_ASSERT(ctx->marks[opener_index+2].ch == 'D');
             md_mark_store_ptr(ctx, opener_index+2, attr.title);
+            /* The title might or might not have been allocated for us. */
             if(attr.title_needs_free)
                 md_mark_chain_append(ctx, &PTR_CHAIN, opener_index+2);
             ctx->marks[opener_index+2].prev = attr.title_size;
@@ -3574,8 +3689,7 @@ md_analyze_emph(MD_CTX* ctx, int mark_index)
             int i, n_opener_chains;
             unsigned flags = mark->flags;
 
-            /* Apply "rule of three". (This is why we break asterisk opener
-             * marks into multiple chains.) */
+            /* Apply the "rule of three". */
             n_opener_chains = 0;
             opener_chains[n_opener_chains++] = &ASTERISK_OPENERS_intraword_mod3_0;
             if((flags & MD_MARK_EMPH_MOD3_MASK) != MD_MARK_EMPH_MOD3_2)
@@ -3611,16 +3725,17 @@ md_analyze_emph(MD_CTX* ctx, int mark_index)
         if(opener != NULL) {
             SZ opener_size = opener->end - opener->beg;
             SZ closer_size = mark->end - mark->beg;
+            MD_MARKCHAIN* opener_chain = md_mark_chain(ctx, opener_index);
 
             if(opener_size > closer_size) {
                 opener_index = md_split_emph_mark(ctx, opener_index, closer_size);
-                md_mark_chain_append(ctx, md_mark_chain(ctx, opener_index), opener_index);
+                md_mark_chain_append(ctx, opener_chain, opener_index);
             } else if(opener_size < closer_size) {
                 md_split_emph_mark(ctx, mark_index, closer_size - opener_size);
             }
 
             md_rollback(ctx, opener_index, mark_index, MD_ROLLBACK_CROSSING);
-            md_resolve_range(ctx, chain, opener_index, mark_index);
+            md_resolve_range(ctx, opener_chain, opener_index, mark_index);
             return;
         }
     }
@@ -3633,20 +3748,23 @@ md_analyze_emph(MD_CTX* ctx, int mark_index)
 static void
 md_analyze_tilde(MD_CTX* ctx, int mark_index)
 {
-    /* We attempt to be Github Flavored Markdown compatible here. GFM says
-     * that length of the tilde sequence is not important at all. Note that
-     * implies the TILDE_OPENERS chain can have at most one item. */
+    MD_MARK* mark = &ctx->marks[mark_index];
+    MD_MARKCHAIN* chain = md_mark_chain(ctx, mark_index);
+
+    /* We attempt to be Github Flavored Markdown compatible here. GFM accepts
+     * only tildes sequences of length 1 and 2, and the length of the opener
+     * and closer has to match. */
 
-    if(TILDE_OPENERS.head >= 0) {
-        /* The chain already contains an opener, so we may resolve the span. */
-        int opener_index = TILDE_OPENERS.head;
+    if((mark->flags & MD_MARK_POTENTIAL_CLOSER)  &&  chain->head >= 0) {
+        int opener_index = chain->head;
 
         md_rollback(ctx, opener_index, mark_index, MD_ROLLBACK_CROSSING);
-        md_resolve_range(ctx, &TILDE_OPENERS, opener_index, mark_index);
-    } else {
-        /* We can only be opener. */
-        md_mark_chain_append(ctx, &TILDE_OPENERS, mark_index);
+        md_resolve_range(ctx, chain, opener_index, mark_index);
+        return;
     }
+
+    if(mark->flags & MD_MARK_POTENTIAL_OPENER)
+        md_mark_chain_append(ctx, chain, mark_index);
 }
 
 static void
@@ -3860,8 +3978,16 @@ md_analyze_inlines(MD_CTX* ctx, const MD_LINE* lines, int n_lines, int table_mod
     /* (1) Entities; code spans; autolinks; raw HTML. */
     md_analyze_marks(ctx, lines, n_lines, 0, ctx->n_marks, _T("&"));
 
+    /* (2) Links. */
+    md_analyze_marks(ctx, lines, n_lines, 0, ctx->n_marks, _T("[]!"));
+    MD_CHECK(md_resolve_links(ctx, lines, n_lines));
+    BRACKET_OPENERS.head = -1;
+    BRACKET_OPENERS.tail = -1;
+    ctx->unresolved_link_head = -1;
+    ctx->unresolved_link_tail = -1;
+
     if(table_mode) {
-        /* (2) Analyze table cell boundaries.
+        /* (3) Analyze table cell boundaries.
          * Note we reset TABLECELLBOUNDARIES chain prior to the call md_analyze_marks(),
          * not after, because caller may need it. */
         MD_ASSERT(n_lines == 1);
@@ -3872,14 +3998,6 @@ md_analyze_inlines(MD_CTX* ctx, const MD_LINE* lines, int n_lines, int table_mod
         return ret;
     }
 
-    /* (3) Links. */
-    md_analyze_marks(ctx, lines, n_lines, 0, ctx->n_marks, _T("[]!"));
-    MD_CHECK(md_resolve_links(ctx, lines, n_lines));
-    BRACKET_OPENERS.head = -1;
-    BRACKET_OPENERS.tail = -1;
-    ctx->unresolved_link_head = -1;
-    ctx->unresolved_link_tail = -1;
-
     /* (4) Emphasis and strong emphasis; permissive autolinks. */
     md_analyze_link_contents(ctx, lines, n_lines, 0, ctx->n_marks);
 
@@ -3891,25 +4009,14 @@ static void
 md_analyze_link_contents(MD_CTX* ctx, const MD_LINE* lines, int n_lines,
                          int mark_beg, int mark_end)
 {
+    int i;
+
     md_analyze_marks(ctx, lines, n_lines, mark_beg, mark_end, _T("*_~$@:."));
-    ASTERISK_OPENERS_extraword_mod3_0.head = -1;
-    ASTERISK_OPENERS_extraword_mod3_0.tail = -1;
-    ASTERISK_OPENERS_extraword_mod3_1.head = -1;
-    ASTERISK_OPENERS_extraword_mod3_1.tail = -1;
-    ASTERISK_OPENERS_extraword_mod3_2.head = -1;
-    ASTERISK_OPENERS_extraword_mod3_2.tail = -1;
-    ASTERISK_OPENERS_intraword_mod3_0.head = -1;
-    ASTERISK_OPENERS_intraword_mod3_0.tail = -1;
-    ASTERISK_OPENERS_intraword_mod3_1.head = -1;
-    ASTERISK_OPENERS_intraword_mod3_1.tail = -1;
-    ASTERISK_OPENERS_intraword_mod3_2.head = -1;
-    ASTERISK_OPENERS_intraword_mod3_2.tail = -1;
-    UNDERSCORE_OPENERS.head = -1;
-    UNDERSCORE_OPENERS.tail = -1;
-    TILDE_OPENERS.head = -1;
-    TILDE_OPENERS.tail = -1;
-    DOLLAR_OPENERS.head = -1;
-    DOLLAR_OPENERS.tail = -1;
+
+    for(i = OPENERS_CHAIN_FIRST; i <= OPENERS_CHAIN_LAST; i++) {
+        ctx->mark_chains[i].head = -1;
+        ctx->mark_chains[i].tail = -1;
+    }
 }
 
 static int
@@ -3941,6 +4048,27 @@ abort:
     return ret;
 }
 
+static int
+md_enter_leave_span_wikilink(MD_CTX* ctx, int enter, const CHAR* target, SZ target_size)
+{
+    MD_ATTRIBUTE_BUILD target_build = { 0 };
+    MD_SPAN_WIKILINK_DETAIL det;
+    int ret = 0;
+
+    memset(&det, 0, sizeof(MD_SPAN_WIKILINK_DETAIL));
+    MD_CHECK(md_build_attribute(ctx, target, target_size, 0, &det.target, &target_build));
+
+    if (enter)
+        MD_ENTER_SPAN(MD_SPAN_WIKILINK, &det);
+    else
+        MD_LEAVE_SPAN(MD_SPAN_WIKILINK, &det);
+
+abort:
+    md_free_attribute(ctx, &target_build);
+    return ret;
+}
+
+
 /* Render the output, accordingly to the analyzed ctx->marks. */
 static int
 md_process_inlines(MD_CTX* ctx, const MD_LINE* lines, int n_lines)
@@ -3996,7 +4124,23 @@ md_process_inlines(MD_CTX* ctx, const MD_LINE* lines, int n_lines)
                     }
                     break;
 
-                case '_':
+                case '_':       /* Underline (or emphasis if we fall through). */
+                    if(ctx->parser.flags & MD_FLAG_UNDERLINE) {
+                        if(mark->flags & MD_MARK_OPENER) {
+                            while(off < mark->end) {
+                                MD_ENTER_SPAN(MD_SPAN_U, NULL);
+                                off++;
+                            }
+                        } else {
+                            while(off < mark->end) {
+                                MD_LEAVE_SPAN(MD_SPAN_U, NULL);
+                                off++;
+                            }
+                        }
+                        break;
+                    }
+                    /* Fall though. */
+
                 case '*':       /* Emphasis, strong emphasis. */
                     if(mark->flags & MD_MARK_OPENER) {
                         if((mark->end - off) % 2) {
@@ -4036,15 +4180,37 @@ md_process_inlines(MD_CTX* ctx, const MD_LINE* lines, int n_lines)
                     }
                     break;
 
-                case '[':       /* Link, image. */
+                case '[':       /* Link, wiki link, image. */
                 case '!':
                 case ']':
                 {
                     const MD_MARK* opener = (mark->ch != ']' ? mark : &ctx->marks[mark->prev]);
-                    const MD_MARK* dest_mark = opener+1;
-                    const MD_MARK* title_mark = opener+2;
+                    const MD_MARK* closer = &ctx->marks[opener->next];
+                    const MD_MARK* dest_mark;
+                    const MD_MARK* title_mark;
+
+                    if ((opener->ch == '[' && closer->ch == ']') &&
+                        opener->end - opener->beg >= 2 &&
+                        closer->end - closer->beg >= 2)
+                    {
+                        int has_label = (opener->end - opener->beg > 2);
+                        SZ target_sz;
+
+                        if(has_label)
+                            target_sz = opener->end - (opener->beg+2);
+                        else
+                            target_sz = closer->beg - opener->end;
 
+                        MD_CHECK(md_enter_leave_span_wikilink(ctx, (mark->ch != ']'),
+                                 has_label ? STR(opener->beg+2) : STR(opener->end),
+                                 target_sz));
+
+                        break;
+                    }
+
+                    dest_mark = opener+1;
                     MD_ASSERT(dest_mark->ch == 'D');
+                    title_mark = opener+2;
                     MD_ASSERT(title_mark->ch == 'D');
 
                     MD_CHECK(md_enter_leave_span_a(ctx, (mark->ch != ']'),
@@ -4251,7 +4417,7 @@ md_process_table_row(MD_CTX* ctx, MD_BLOCKTYPE cell_type, OFF beg, OFF end,
 {
     MD_LINE line;
     OFF* pipe_offs = NULL;
-    int i, j, n;
+    int i, j, k, n;
     int ret = 0;
 
     line.beg = beg;
@@ -4263,32 +4429,32 @@ md_process_table_row(MD_CTX* ctx, MD_BLOCKTYPE cell_type, OFF beg, OFF end,
 
     /* We have to remember the cell boundaries in local buffer because
      * ctx->marks[] shall be reused during cell contents processing. */
-    n = ctx->n_table_cell_boundaries;
+    n = ctx->n_table_cell_boundaries + 2;
     pipe_offs = (OFF*) malloc(n * sizeof(OFF));
     if(pipe_offs == NULL) {
         MD_LOG("malloc() failed.");
         ret = -1;
         goto abort;
     }
-    for(i = TABLECELLBOUNDARIES.head, j = 0; i >= 0; i = ctx->marks[i].next) {
+    j = 0;
+    pipe_offs[j++] = beg;
+    for(i = TABLECELLBOUNDARIES.head; i >= 0; i = ctx->marks[i].next) {
         MD_MARK* mark = &ctx->marks[i];
-        pipe_offs[j++] = mark->beg;
+        pipe_offs[j++] = mark->end;
     }
+    pipe_offs[j++] = end+1;
 
     /* Process cells. */
     MD_ENTER_BLOCK(MD_BLOCK_TR, NULL);
-    j = 0;
-    if(beg < pipe_offs[0]  &&  j < col_count)
-        MD_CHECK(md_process_table_cell(ctx, cell_type, align[j++], beg, pipe_offs[0]));
-    for(i = 0; i < n-1  &&  j < col_count; i++)
-        MD_CHECK(md_process_table_cell(ctx, cell_type, align[j++], pipe_offs[i]+1, pipe_offs[i+1]));
-    if(pipe_offs[n-1] < end-1  &&  j < col_count)
-        MD_CHECK(md_process_table_cell(ctx, cell_type, align[j++], pipe_offs[n-1]+1, end));
+    k = 0;
+    for(i = 0; i < j-1  &&  k < col_count; i++) {
+        if(pipe_offs[i] < pipe_offs[i+1]-1)
+            MD_CHECK(md_process_table_cell(ctx, cell_type, align[k++], pipe_offs[i], pipe_offs[i+1]-1));
+    }
     /* Make sure we call enough table cells even if the current table contains
      * too few of them. */
-    while(j < col_count)
-        MD_CHECK(md_process_table_cell(ctx, cell_type, align[j++], 0, 0));
-
+    while(k < col_count)
+        MD_CHECK(md_process_table_cell(ctx, cell_type, align[k++], 0, 0));
     MD_LEAVE_BLOCK(MD_BLOCK_TR, NULL);
 
 abort:
@@ -4340,38 +4506,6 @@ abort:
     return ret;
 }
 
-static int
-md_is_table_row(MD_CTX* ctx, OFF beg, OFF* p_end)
-{
-    MD_LINE line;
-    int i;
-    int ret = FALSE;
-
-    line.beg = beg;
-    line.end = beg;
-
-    /* Find end of line. */
-    while(line.end < ctx->size  &&  !ISNEWLINE(line.end))
-        line.end++;
-
-    MD_CHECK(md_analyze_inlines(ctx, &line, 1, TRUE));
-
-    if(TABLECELLBOUNDARIES.head >= 0) {
-        if(p_end != NULL)
-            *p_end = line.end;
-        ret = TRUE;
-    }
-
-abort:
-    /* Free any temporary memory blocks stored within some dummy marks. */
-    for(i = PTR_CHAIN.head; i >= 0; i = ctx->marks[i].next)
-        free(md_mark_get_ptr(ctx, i));
-    PTR_CHAIN.head = -1;
-    PTR_CHAIN.tail = -1;
-
-    return ret;
-}
-
 
 /**************************
  ***  Processing Block  ***
@@ -4704,7 +4838,9 @@ md_push_block_bytes(MD_CTX* ctx, int n_bytes)
     if(ctx->n_block_bytes + n_bytes > ctx->alloc_block_bytes) {
         void* new_block_bytes;
 
-        ctx->alloc_block_bytes = (ctx->alloc_block_bytes > 0 ? ctx->alloc_block_bytes * 2 : 512);
+        ctx->alloc_block_bytes = (ctx->alloc_block_bytes > 0
+                ? ctx->alloc_block_bytes + ctx->alloc_block_bytes / 2
+                : 512);
         new_block_bytes = realloc(ctx->block_bytes, ctx->alloc_block_bytes);
         if(new_block_bytes == NULL) {
             MD_LOG("realloc() failed.");
@@ -5136,7 +5272,7 @@ md_is_html_block_start_condition(MD_CTX* ctx, OFF beg)
 #ifdef X
     #undef X
 #endif
-#define X(name)     { _T(name), sizeof(name)-1 }
+#define X(name)     { _T(name), (sizeof(name)-1) / sizeof(CHAR) }
 #define Xend        { NULL, 0 }
     static const TAG t1[] = { X("script"), X("pre"), X("style"), Xend };
 
@@ -5192,7 +5328,7 @@ md_is_html_block_start_condition(MD_CTX* ctx, OFF beg)
 
         /* Check for type 5: <![CDATA[ */
         if(off + 8 < ctx->size) {
-            if(md_ascii_eq(STR(off), _T("![CDATA["), 8 * sizeof(CHAR)))
+            if(md_ascii_eq(STR(off), _T("![CDATA["), 8))
                 return 5;
         }
     }
@@ -5341,7 +5477,9 @@ md_push_container(MD_CTX* ctx, const MD_CONTAINER* container)
     if(ctx->n_containers >= ctx->alloc_containers) {
         MD_CONTAINER* new_containers;
 
-        ctx->alloc_containers = (ctx->alloc_containers > 0 ? ctx->alloc_containers * 2 : 16);
+        ctx->alloc_containers = (ctx->alloc_containers > 0
+                ? ctx->alloc_containers + ctx->alloc_containers / 2
+                : 16);
         new_containers = realloc(ctx->containers, ctx->alloc_containers * sizeof(MD_CONTAINER));
         if(new_containers == NULL) {
             MD_LOG("realloc() failed.");
@@ -5561,6 +5699,7 @@ md_analyze_line(MD_CTX* ctx, OFF beg, OFF* p_end,
                 line->indent--;
 
             line->beg = off;
+
         } else if(c->ch != _T('>')  &&  line->indent >= c->contents_indent) {
             /* List. */
             line->indent -= c->contents_indent;
@@ -5803,9 +5942,7 @@ md_analyze_line(MD_CTX* ctx, OFF beg, OFF* p_end,
         }
 
         /* Check whether we are table continuation. */
-        if(pivot_line->type == MD_LINE_TABLE  &&  md_is_table_row(ctx, off, &off)  &&
-           n_parents == ctx->n_containers)
-        {
+        if(pivot_line->type == MD_LINE_TABLE  &&  n_parents == ctx->n_containers) {
             line->type = MD_LINE_TABLE;
             break;
         }
@@ -5859,8 +5996,7 @@ md_analyze_line(MD_CTX* ctx, OFF beg, OFF* p_end,
             unsigned col_count;
 
             if(ctx->current_block != NULL  &&  ctx->current_block->n_lines == 1  &&
-                md_is_table_underline(ctx, off, &off, &col_count)  &&
-                md_is_table_row(ctx, pivot_line->beg, NULL))
+                md_is_table_underline(ctx, off, &off, &col_count))
             {
                 line->data = col_count;
                 line->type = MD_LINE_TABLEUNDERLINE;
diff --git a/src/3rdparty/md4c/md4c.h b/src/3rdparty/md4c/md4c.h
index 6d9fce5180..c2c4311f50 100644
--- a/src/3rdparty/md4c/md4c.h
+++ b/src/3rdparty/md4c/md4c.h
@@ -2,7 +2,7 @@
  * MD4C: Markdown parser for C
  * (http://github.com/mity/md4c)
  *
- * Copyright (c) 2016-2019 Martin Mitas
+ * Copyright (c) 2016-2020 Martin Mitas
  *
  * Permission is hereby granted, free of charge, to any person obtaining a
  * copy of this software and associated documentation files (the "Software"),
@@ -135,7 +135,16 @@ typedef enum MD_SPANTYPE {
      * Note: Recognized only when MD_FLAG_LATEXMATHSPANS is enabled.
      */
     MD_SPAN_LATEXMATH,
-    MD_SPAN_LATEXMATH_DISPLAY
+    MD_SPAN_LATEXMATH_DISPLAY,
+
+    /* Wiki links
+     * Note: Recognized only when MD_FLAG_WIKILINKS is enabled.
+     */
+    MD_SPAN_WIKILINK,
+
+    /* <u>...</u>
+     * Note: Recognized only when MD_FLAG_UNDERLINE is enabled. */
+    MD_SPAN_U
 } MD_SPANTYPE;
 
 /* Text is the actual textual contents of span. */
@@ -268,6 +277,10 @@ typedef struct MD_SPAN_IMG_DETAIL {
     MD_ATTRIBUTE title;
 } MD_SPAN_IMG_DETAIL;
 
+/* Detailed info for MD_SPAN_WIKILINK. */
+typedef struct MD_SPAN_WIKILINK {
+    MD_ATTRIBUTE target;
+} MD_SPAN_WIKILINK_DETAIL;
 
 /* Flags specifying extensions/deviations from CommonMark specification.
  *
@@ -286,6 +299,8 @@ typedef struct MD_SPAN_IMG_DETAIL {
 #define MD_FLAG_PERMISSIVEWWWAUTOLINKS      0x0400  /* Enable WWW autolinks (even without any scheme prefix, if they begin with 'www.') */
 #define MD_FLAG_TASKLISTS                   0x0800  /* Enable task list extension. */
 #define MD_FLAG_LATEXMATHSPANS              0x1000  /* Enable $ and $$ containing LaTeX equations. */
+#define MD_FLAG_WIKILINKS                   0x2000  /* Enable wiki links extension. */
+#define MD_FLAG_UNDERLINE                   0x4000  /* Enable underline extension (and disables '_' for normal emphasis). */
 
 #define MD_FLAG_PERMISSIVEAUTOLINKS         (MD_FLAG_PERMISSIVEEMAILAUTOLINKS | MD_FLAG_PERMISSIVEURLAUTOLINKS | MD_FLAG_PERMISSIVEWWWAUTOLINKS)
 #define MD_FLAG_NOHTML                      (MD_FLAG_NOHTMLBLOCKS | MD_FLAG_NOHTMLSPANS)
diff --git a/src/3rdparty/md4c/qt_attribution.json b/src/3rdparty/md4c/qt_attribution.json
index 5fd77269e9..c574b97711 100644
--- a/src/3rdparty/md4c/qt_attribution.json
+++ b/src/3rdparty/md4c/qt_attribution.json
@@ -9,7 +9,7 @@
     "License": "MIT License",
     "LicenseId": "MIT",
     "LicenseFile": "LICENSE.md",
-    "Version": "0.3.4",
-    "DownloadLocation": "https://github.com/mity/md4c/releases/tag/release-0.3.4",
-    "Copyright": "Copyright © 2016-2019 Martin Mitáš"
+    "Version": "0.4.3",
+    "DownloadLocation": "https://github.com/mity/md4c/releases/tag/release-0.4.3",
+    "Copyright": "Copyright © 2016-2020 Martin Mitáš"
 }
diff --git a/src/plugins/styles/windowsvista/qwindowsvistastyle.cpp b/src/plugins/styles/windowsvista/qwindowsvistastyle.cpp
index e8d74180cd..30b3786a80 100644
--- a/src/plugins/styles/windowsvista/qwindowsvistastyle.cpp
+++ b/src/plugins/styles/windowsvista/qwindowsvistastyle.cpp
@@ -2217,7 +2217,7 @@ QRect QWindowsVistaStyle::subControlRect(ComplexControl control, const QStyleOpt
                 {
                     const int controlTop = int(6 * factor);
                     const int controlHeight = int(height - controlTop - 3 * factor);
-                    int iconExtent = proxy()->pixelMetric(PM_SmallIconSize);
+                    int iconExtent = proxy()->pixelMetric(PM_SmallIconSize, option);
                     QSize iconSize = tb->icon.actualSize(QSize(iconExtent, iconExtent));
                     if (tb->icon.isNull())
                         iconSize = QSize(controlHeight, controlHeight);
diff --git a/src/plugins/styles/windowsvista/qwindowsxpstyle.cpp b/src/plugins/styles/windowsvista/qwindowsxpstyle.cpp
index 9d143da169..e43746e79f 100644
--- a/src/plugins/styles/windowsvista/qwindowsxpstyle.cpp
+++ b/src/plugins/styles/windowsvista/qwindowsxpstyle.cpp
@@ -3453,7 +3453,7 @@ QRect QWindowsXPStyle::subControlRect(ComplexControl cc, const QStyleOptionCompl
                 {
                     const int controlTop = 6;
                     const int controlHeight = height - controlTop - 3;
-                    const int iconExtent = proxy()->pixelMetric(PM_SmallIconSize);
+                    const int iconExtent = proxy()->pixelMetric(PM_SmallIconSize, option);
                     QSize iconSize = tb->icon.actualSize(QSize(iconExtent, iconExtent));
                     if (tb->icon.isNull())
                         iconSize = QSize(controlHeight, controlHeight);
@@ -3575,7 +3575,7 @@ QSize QWindowsXPStyle::sizeFromContents(ContentsType ct, const QStyleOption *opt
                     sz.rheight() += int(borderSize.bottom() + borderSize.top() - margin
                         + qreal(1) / factor - 1);
                 }
-                const int textMargins = 2*(proxy()->pixelMetric(PM_FocusFrameHMargin) + 1);
+                const int textMargins = 2*(proxy()->pixelMetric(PM_FocusFrameHMargin, option) + 1);
                 sz += QSize(qMax(pixelMetric(QStyle::PM_ScrollBarExtent, option, widget)
                                  + textMargins, 23), 0); //arrow button
             }
diff --git a/src/widgets/dialogs/qcolordialog.cpp b/src/widgets/dialogs/qcolordialog.cpp
index 689002b589..4247731275 100644
--- a/src/widgets/dialogs/qcolordialog.cpp
+++ b/src/widgets/dialogs/qcolordialog.cpp
@@ -346,7 +346,8 @@ void QWellArray::paintCell(QPainter* p, int row, int col, const QRect &rect)
 
     const QPalette & g = palette();
     QStyleOptionFrame opt;
-    int dfw = style()->pixelMetric(QStyle::PM_DefaultFrameWidth);
+    opt.initFrom(this);
+    int dfw = style()->pixelMetric(QStyle::PM_DefaultFrameWidth, &opt);
     opt.lineWidth = dfw;
     opt.midLineWidth = 1;
     opt.rect = rect.adjusted(b, b, -b, -b);
diff --git a/src/widgets/dialogs/qwizard.cpp b/src/widgets/dialogs/qwizard.cpp
index 87f6875c8c..31e32bb931 100644
--- a/src/widgets/dialogs/qwizard.cpp
+++ b/src/widgets/dialogs/qwizard.cpp
@@ -64,6 +64,7 @@
 #  include "qshortcut.h"
 #endif
 #include "qstyle.h"
+#include "qstyleoption.h"
 #include "qvarlengtharray.h"
 #if defined(Q_OS_MACX)
 #include <QtCore/QMetaMethod>
@@ -897,7 +898,9 @@ QWizardLayoutInfo QWizardPrivate::layoutInfoForCurrentPage()
 
     QWizardLayoutInfo info;
 
-    const int layoutHorizontalSpacing = style->pixelMetric(QStyle::PM_LayoutHorizontalSpacing);
+    QStyleOption option;
+    option.initFrom(q);
+    const int layoutHorizontalSpacing = style->pixelMetric(QStyle::PM_LayoutHorizontalSpacing, &option);
     info.topLevelMarginLeft = style->pixelMetric(QStyle::PM_LayoutLeftMargin, nullptr, q);
     info.topLevelMarginRight = style->pixelMetric(QStyle::PM_LayoutRightMargin, nullptr, q);
     info.topLevelMarginTop = style->pixelMetric(QStyle::PM_LayoutTopMargin, nullptr, q);
@@ -909,7 +912,7 @@ QWizardLayoutInfo QWizardPrivate::layoutInfoForCurrentPage()
     info.hspacing = (layoutHorizontalSpacing == -1)
         ? style->layoutSpacing(QSizePolicy::DefaultType, QSizePolicy::DefaultType, Qt::Horizontal)
         : layoutHorizontalSpacing;
-    info.vspacing = style->pixelMetric(QStyle::PM_LayoutVerticalSpacing);
+    info.vspacing = style->pixelMetric(QStyle::PM_LayoutVerticalSpacing, &option);
     info.buttonSpacing = (layoutHorizontalSpacing == -1)
         ? style->layoutSpacing(QSizePolicy::PushButton, QSizePolicy::PushButton, Qt::Horizontal)
         : layoutHorizontalSpacing;
diff --git a/src/widgets/graphicsview/qgraphicslayout_p.h b/src/widgets/graphicsview/qgraphicslayout_p.h
index 0d91151e22..9e86ae2f76 100644
--- a/src/widgets/graphicsview/qgraphicslayout_p.h
+++ b/src/widgets/graphicsview/qgraphicslayout_p.h
@@ -87,8 +87,8 @@ public:
         Q_ASSERT(style);
         if (widget) //###
             m_styleOption.initFrom(widget);
-        m_defaultSpacing[0] = style->pixelMetric(QStyle::PM_LayoutHorizontalSpacing);
-        m_defaultSpacing[1] = style->pixelMetric(QStyle::PM_LayoutVerticalSpacing);
+        m_defaultSpacing[0] = style->pixelMetric(QStyle::PM_LayoutHorizontalSpacing, &m_styleOption);
+        m_defaultSpacing[1] = style->pixelMetric(QStyle::PM_LayoutVerticalSpacing, &m_styleOption);
     }
 
     inline void invalidate() { m_valid = false; m_style = nullptr; m_widget = nullptr; }
diff --git a/src/widgets/graphicsview/qgraphicslayoutstyleinfo.cpp b/src/widgets/graphicsview/qgraphicslayoutstyleinfo.cpp
index 2f1526cc78..58b9f8bb9d 100644
--- a/src/widgets/graphicsview/qgraphicslayoutstyleinfo.cpp
+++ b/src/widgets/graphicsview/qgraphicslayoutstyleinfo.cpp
@@ -80,7 +80,9 @@ qreal QGraphicsLayoutStyleInfo::perItemSpacing(QLayoutPolicy::ControlType contro
 qreal QGraphicsLayoutStyleInfo::spacing(Qt::Orientation orientation) const
 {
     Q_ASSERT(style());
-    return style()->pixelMetric(orientation == Qt::Horizontal ? QStyle::PM_LayoutHorizontalSpacing : QStyle::PM_LayoutVerticalSpacing);
+    return style()->pixelMetric(orientation == Qt::Horizontal
+        ? QStyle::PM_LayoutHorizontalSpacing : QStyle::PM_LayoutVerticalSpacing,
+        &m_styleOption);
 }
 
 qreal QGraphicsLayoutStyleInfo::windowMargin(Qt::Orientation orientation) const
diff --git a/src/widgets/graphicsview/qgraphicswidget.cpp b/src/widgets/graphicsview/qgraphicswidget.cpp
index 1035ed3575..6242314e1d 100644
--- a/src/widgets/graphicsview/qgraphicswidget.cpp
+++ b/src/widgets/graphicsview/qgraphicswidget.cpp
@@ -615,7 +615,7 @@ void QGraphicsWidget::unsetWindowFrameMargins()
         QStyleOptionTitleBar bar;
         d->initStyleOptionTitleBar(&bar);
         QStyle *style = this->style();
-        qreal margin = style->pixelMetric(QStyle::PM_MdiSubWindowFrameWidth);
+        const qreal margin = style->pixelMetric(QStyle::PM_MdiSubWindowFrameWidth, &bar);
         qreal titleBarHeight  = d->titleBarHeight(bar);
         setWindowFrameMargins(margin, titleBarHeight, margin, margin);
     } else {
diff --git a/src/widgets/itemviews/qabstractitemview.cpp b/src/widgets/itemviews/qabstractitemview.cpp
index 5b92fc6790..ebef36d033 100644
--- a/src/widgets/itemviews/qabstractitemview.cpp
+++ b/src/widgets/itemviews/qabstractitemview.cpp
@@ -3235,8 +3235,10 @@ void QAbstractItemView::setIndexWidget(const QModelIndex &index, QWidget *widget
         widget->installEventFilter(this);
         widget->show();
         dataChanged(index, index); // update the geometry
-        if (!d->delayedPendingLayout)
+        if (!d->delayedPendingLayout) {
             widget->setGeometry(visualRect(index));
+            d->doDelayedItemsLayout();  // relayout due to updated geometry
+        }
     }
 }
 
diff --git a/src/widgets/itemviews/qitemdelegate.cpp b/src/widgets/itemviews/qitemdelegate.cpp
index 4420d39b8e..40ad48c655 100644
--- a/src/widgets/itemviews/qitemdelegate.cpp
+++ b/src/widgets/itemviews/qitemdelegate.cpp
@@ -1122,7 +1122,7 @@ QRect QItemDelegate::textRectangle(QPainter * /*painter*/, const QRect &rect,
     QSizeF fpSize = d->doTextLayout(rect.width());
     const QSize size = QSize(qCeil(fpSize.width()), qCeil(fpSize.height()));
     // ###: textRectangle should take style option as argument
-    const int textMargin = QApplication::style()->pixelMetric(QStyle::PM_FocusFrameHMargin) + 1;
+    const int textMargin = QApplication::style()->pixelMetric(QStyle::PM_FocusFrameHMargin, nullptr) + 1;
     return QRect(0, 0, size.width() + 2 * textMargin, size.height());
 }
 
diff --git a/src/widgets/itemviews/qlistview.cpp b/src/widgets/itemviews/qlistview.cpp
index ec01922746..4cb9214ff4 100644
--- a/src/widgets/itemviews/qlistview.cpp
+++ b/src/widgets/itemviews/qlistview.cpp
@@ -1728,8 +1728,11 @@ void QListViewPrivate::prepareItemsLayout()
     layoutBounds = QRect(QPoint(), q->maximumViewportSize());
 
     int frameAroundContents = 0;
-    if (q->style()->styleHint(QStyle::SH_ScrollView_FrameOnlyAroundContents))
-        frameAroundContents = q->style()->pixelMetric(QStyle::PM_DefaultFrameWidth) * 2;
+    if (q->style()->styleHint(QStyle::SH_ScrollView_FrameOnlyAroundContents)) {
+        QStyleOption option;
+        option.initFrom(q);
+        frameAroundContents = q->style()->pixelMetric(QStyle::PM_DefaultFrameWidth, &option) * 2;
+    }
 
     // maximumViewportSize() already takes scrollbar into account if policy is
     // Qt::ScrollBarAlwaysOn but scrollbar extent must be deduced if policy
diff --git a/src/widgets/styles/qcommonstyle.cpp b/src/widgets/styles/qcommonstyle.cpp
index f4a53c9dfe..4b0094e578 100644
--- a/src/widgets/styles/qcommonstyle.cpp
+++ b/src/widgets/styles/qcommonstyle.cpp
@@ -431,7 +431,7 @@ void QCommonStyle::drawPrimitive(PrimitiveElement pe, const QStyleOption *opt, Q
                         QIcon::Active, QIcon::Off);
         }
 
-        int size = proxy()->pixelMetric(QStyle::PM_SmallIconSize);
+        const int size = proxy()->pixelMetric(QStyle::PM_SmallIconSize, opt);
         QIcon::Mode mode = opt->state & State_Enabled ?
                             (opt->state & State_Raised ? QIcon::Active : QIcon::Normal)
                             : QIcon::Disabled;
@@ -477,7 +477,7 @@ void QCommonStyle::drawPrimitive(PrimitiveElement pe, const QStyleOption *opt, Q
         if (const QStyleOptionFrame *frame = qstyleoption_cast<const QStyleOptionFrame *>(opt)) {
             int lw = frame->lineWidth;
             if (lw <= 0)
-                lw = proxy()->pixelMetric(PM_DockWidgetFrameWidth);
+                lw = proxy()->pixelMetric(PM_DockWidgetFrameWidth, opt);
 
             qDrawShadePanel(p, frame->rect, frame->palette, false, lw);
         }
@@ -563,8 +563,8 @@ void QCommonStyle::drawPrimitive(PrimitiveElement pe, const QStyleOption *opt, Q
         int bsx = 0;
         int bsy = 0;
         if (opt->state & State_Sunken) {
-            bsx = proxy()->pixelMetric(PM_ButtonShiftHorizontal);
-            bsy = proxy()->pixelMetric(PM_ButtonShiftVertical);
+            bsx = proxy()->pixelMetric(PM_ButtonShiftHorizontal, opt);
+            bsy = proxy()->pixelMetric(PM_ButtonShiftVertical, opt);
         }
         p->save();
         p->translate(sx + bsx, sy + bsy);
@@ -994,7 +994,7 @@ QSize QCommonStylePrivate::viewItemSize(const QStyleOptionViewItem *option, int
             }
 
             if (wrapText && option->features & QStyleOptionViewItem::HasCheckIndicator)
-                bounds.setWidth(bounds.width() - proxyStyle->pixelMetric(QStyle::PM_IndicatorWidth) - 2 * textMargin);
+                bounds.setWidth(bounds.width() - proxyStyle->pixelMetric(QStyle::PM_IndicatorWidth, option) - 2 * textMargin);
 
             const int lineWidth = bounds.width();
             const QSizeF size = viewItemTextLayout(textLayout, lineWidth);
@@ -1240,7 +1240,7 @@ void QCommonStylePrivate::tabLayout(const QStyleOptionTab *opt, const QWidget *w
     if (!opt->icon.isNull()) {
         QSize iconSize = opt->iconSize;
         if (!iconSize.isValid()) {
-            int iconExtent = proxyStyle->pixelMetric(QStyle::PM_SmallIconSize);
+            int iconExtent = proxyStyle->pixelMetric(QStyle::PM_SmallIconSize, opt);
             iconSize = QSize(iconExtent, iconExtent);
         }
         QSize tabIconSize = opt->icon.actualSize(iconSize,
@@ -1490,7 +1490,7 @@ void QCommonStyle::drawControl(ControlElement element, const QStyleOption *opt,
                             | Qt::TextSingleLine;
             if (!proxy()->styleHint(SH_UnderlineShortcut, mbi, widget))
                 alignment |= Qt::TextHideMnemonic;
-            int iconExtent = proxy()->pixelMetric(PM_SmallIconSize);
+            int iconExtent = proxy()->pixelMetric(PM_SmallIconSize, opt);
             QPixmap pix = mbi->icon.pixmap(qt_getWindow(widget), QSize(iconExtent, iconExtent), (mbi->state & State_Enabled) ? QIcon::Normal : QIcon::Disabled);
             if (!pix.isNull())
                 proxy()->drawItemPixmap(p,mbi->rect, alignment, pix);
@@ -1646,7 +1646,7 @@ void QCommonStyle::drawControl(ControlElement element, const QStyleOption *opt,
         if (const QStyleOptionHeader *header = qstyleoption_cast<const QStyleOptionHeader *>(opt)) {
             QRect rect = header->rect;
             if (!header->icon.isNull()) {
-                int iconExtent = proxy()->pixelMetric(PM_SmallIconSize);
+                int iconExtent = proxy()->pixelMetric(PM_SmallIconSize, opt);
                 QPixmap pixmap
                     = header->icon.pixmap(qt_getWindow(widget), QSize(iconExtent, iconExtent), (header->state & State_Enabled) ? QIcon::Normal : QIcon::Disabled);
                 int pixw = pixmap.width() / pixmap.devicePixelRatio();
@@ -3863,8 +3863,8 @@ void QCommonStyle::drawComplexControl(ComplexControl cc, const QStyleOptionCompl
                 if (opt->activeSubControls & QStyle::SC_MdiCloseButton && (opt->state & State_Sunken)) {
                     btnOpt.state |= State_Sunken;
                     btnOpt.state &= ~State_Raised;
-                    bsx = proxy()->pixelMetric(PM_ButtonShiftHorizontal);
-                    bsy = proxy()->pixelMetric(PM_ButtonShiftVertical);
+                    bsx = proxy()->pixelMetric(PM_ButtonShiftHorizontal, opt);
+                    bsy = proxy()->pixelMetric(PM_ButtonShiftVertical, opt);
                 } else {
                     btnOpt.state |= State_Raised;
                     btnOpt.state &= ~State_Sunken;
@@ -3880,8 +3880,8 @@ void QCommonStyle::drawComplexControl(ComplexControl cc, const QStyleOptionCompl
                 if (opt->activeSubControls & QStyle::SC_MdiNormalButton && (opt->state & State_Sunken)) {
                     btnOpt.state |= State_Sunken;
                     btnOpt.state &= ~State_Raised;
-                    bsx = proxy()->pixelMetric(PM_ButtonShiftHorizontal);
-                    bsy = proxy()->pixelMetric(PM_ButtonShiftVertical);
+                    bsx = proxy()->pixelMetric(PM_ButtonShiftHorizontal, opt);
+                    bsy = proxy()->pixelMetric(PM_ButtonShiftVertical, opt);
                 } else {
                     btnOpt.state |= State_Raised;
                     btnOpt.state &= ~State_Sunken;
@@ -3897,8 +3897,8 @@ void QCommonStyle::drawComplexControl(ComplexControl cc, const QStyleOptionCompl
                 if (opt->activeSubControls & QStyle::SC_MdiMinButton && (opt->state & State_Sunken)) {
                     btnOpt.state |= State_Sunken;
                     btnOpt.state &= ~State_Raised;
-                    bsx = proxy()->pixelMetric(PM_ButtonShiftHorizontal);
-                    bsy = proxy()->pixelMetric(PM_ButtonShiftVertical);
+                    bsx = proxy()->pixelMetric(PM_ButtonShiftHorizontal, opt);
+                    bsy = proxy()->pixelMetric(PM_ButtonShiftVertical, opt);
                 } else {
                     btnOpt.state |= State_Raised;
                     btnOpt.state &= ~State_Sunken;
@@ -4781,12 +4781,12 @@ int QCommonStyle::pixelMetric(PixelMetric m, const QStyleOption *opt, const QWid
             } else if (widget) {
                 isWindow = widget->isWindow();
             }
-            ret = proxy()->pixelMetric(isWindow ? PM_DefaultTopLevelMargin : PM_DefaultChildMargin);
+            ret = proxy()->pixelMetric(isWindow ? PM_DefaultTopLevelMargin : PM_DefaultChildMargin, opt);
         }
         break;
     case PM_LayoutHorizontalSpacing:
     case PM_LayoutVerticalSpacing:
-        ret = proxy()->pixelMetric(PM_DefaultLayoutSpacing);
+        ret = proxy()->pixelMetric(PM_DefaultLayoutSpacing, opt);
         break;
 
     case PM_DefaultTopLevelMargin:
@@ -4937,7 +4937,7 @@ QSize QCommonStyle::sizeFromContents(ContentsType ct, const QStyleOption *opt,
             } else {
                 h =  mi->fontMetrics.height() + 8;
                 if (!mi->icon.isNull()) {
-                    int iconExtent = proxy()->pixelMetric(PM_SmallIconSize);
+                    int iconExtent = proxy()->pixelMetric(PM_SmallIconSize, opt);
                     h = qMax(h, mi->icon.actualSize(QSize(iconExtent, iconExtent)).height() + 4);
                 }
             }
@@ -4963,7 +4963,7 @@ QSize QCommonStyle::sizeFromContents(ContentsType ct, const QStyleOption *opt,
     case CT_ComboBox:
         if (const QStyleOptionComboBox *cmb = qstyleoption_cast<const QStyleOptionComboBox *>(opt)) {
             int fw = cmb->frame ? proxy()->pixelMetric(PM_ComboBoxFrameWidth, opt, widget) * 2 : 0;
-            const int textMargins = 2*(proxy()->pixelMetric(PM_FocusFrameHMargin) + 1);
+            const int textMargins = 2*(proxy()->pixelMetric(PM_FocusFrameHMargin, opt) + 1);
             // QItemDelegate::sizeHint expands the textMargins two times, thus the 2*textMargins...
             int other = qMax(23, 2*textMargins + proxy()->pixelMetric(QStyle::PM_ScrollBarExtent, opt, widget));
             sz = QSize(sz.width() + fw + other, sz.height() + fw);
@@ -5214,8 +5214,8 @@ int QCommonStyle::styleHint(StyleHint sh, const QStyleOption *opt, const QWidget
         if (widget) {
             if(QStyleHintReturnMask *mask = qstyleoption_cast<QStyleHintReturnMask*>(hret)) {
                 mask->region = widget->rect();
-                int vmargin = proxy()->pixelMetric(QStyle::PM_FocusFrameVMargin),
-                    hmargin = proxy()->pixelMetric(QStyle::PM_FocusFrameHMargin);
+                const int vmargin = proxy()->pixelMetric(QStyle::PM_FocusFrameVMargin, opt);
+                const int hmargin = proxy()->pixelMetric(QStyle::PM_FocusFrameHMargin, opt);
                 mask->region -= QRect(widget->rect().adjusted(hmargin, vmargin, -hmargin, -vmargin));
             }
         }
@@ -5228,7 +5228,7 @@ int QCommonStyle::styleHint(StyleHint sh, const QStyleOption *opt, const QWidget
                 ret = true;
                 if(QStyleHintReturnMask *mask = qstyleoption_cast<QStyleHintReturnMask*>(hret)) {
                     mask->region = opt->rect;
-                    int margin = proxy()->pixelMetric(PM_DefaultFrameWidth) * 2;
+                    const int margin = proxy()->pixelMetric(PM_DefaultFrameWidth, opt) * 2;
                     mask->region -= opt->rect.adjusted(margin, margin, -margin, -margin);
                 }
             }
diff --git a/src/widgets/styles/qfusionstyle.cpp b/src/widgets/styles/qfusionstyle.cpp
index 45154ee647..ce5f084618 100644
--- a/src/widgets/styles/qfusionstyle.cpp
+++ b/src/widgets/styles/qfusionstyle.cpp
@@ -3349,8 +3349,8 @@ QRect QFusionStyle::subControlRect(ComplexControl control, const QStyleOptionCom
             switch (subControl) {
             case SC_SliderHandle: {
                 if (slider->orientation == Qt::Horizontal) {
-                    rect.setHeight(proxy()->pixelMetric(PM_SliderThickness));
-                    rect.setWidth(proxy()->pixelMetric(PM_SliderLength));
+                    rect.setHeight(proxy()->pixelMetric(PM_SliderThickness, option));
+                    rect.setWidth(proxy()->pixelMetric(PM_SliderLength, option));
                     int centerY = slider->rect.center().y() - rect.height() / 2;
                     if (slider->tickPosition & QSlider::TicksAbove)
                         centerY += tickSize;
@@ -3358,8 +3358,8 @@ QRect QFusionStyle::subControlRect(ComplexControl control, const QStyleOptionCom
                         centerY -= tickSize;
                     rect.moveTop(centerY);
                 } else {
-                    rect.setWidth(proxy()->pixelMetric(PM_SliderThickness));
-                    rect.setHeight(proxy()->pixelMetric(PM_SliderLength));
+                    rect.setWidth(proxy()->pixelMetric(PM_SliderThickness, option));
+                    rect.setHeight(proxy()->pixelMetric(PM_SliderLength, option));
                     int centerX = slider->rect.center().x() - rect.width() / 2;
                     if (slider->tickPosition & QSlider::TicksAbove)
                         centerX += tickSize;
diff --git a/src/widgets/styles/qpixmapstyle.cpp b/src/widgets/styles/qpixmapstyle.cpp
index 05e8467528..7cc32b2039 100644
--- a/src/widgets/styles/qpixmapstyle.cpp
+++ b/src/widgets/styles/qpixmapstyle.cpp
@@ -1003,13 +1003,13 @@ QSize QPixmapStyle::pushButtonSizeFromContents(const QStyleOption *option,
     return d->computeSize(desc, w, h);
 }
 
-QSize QPixmapStyle::lineEditSizeFromContents(const QStyleOption *,
+QSize QPixmapStyle::lineEditSizeFromContents(const QStyleOption *option,
                                              const QSize &contentsSize, const QWidget *) const
 {
     Q_D(const QPixmapStyle);
 
     const QPixmapStyleDescriptor &desc = d->descriptors.value(LE_Enabled);
-    const int border = 2 * proxy()->pixelMetric(PM_DefaultFrameWidth);
+    const int border = 2 * proxy()->pixelMetric(PM_DefaultFrameWidth, option);
 
     int w = contentsSize.width() + border + desc.margins.left() + desc.margins.right();
     int h = contentsSize.height() + border + desc.margins.top() + desc.margins.bottom();
diff --git a/src/widgets/widgets/qcalendarwidget.cpp b/src/widgets/widgets/qcalendarwidget.cpp
index fe1133c6c7..570ec72377 100644
--- a/src/widgets/widgets/qcalendarwidget.cpp
+++ b/src/widgets/widgets/qcalendarwidget.cpp
@@ -2232,7 +2232,9 @@ QSize QCalendarWidget::minimumSizeHint() const
     int rows = 7;
     int cols = 8;
 
-    const int marginH = (style()->pixelMetric(QStyle::PM_FocusFrameHMargin) + 1) * 2;
+    QStyleOption option;
+    option.initFrom(this);
+    const int marginH = (style()->pixelMetric(QStyle::PM_FocusFrameHMargin, &option) + 1) * 2;
 
     if (horizontalHeaderFormat() == QCalendarWidget::NoHorizontalHeader) {
         rows = 6;
diff --git a/src/widgets/widgets/qcombobox_p.h b/src/widgets/widgets/qcombobox_p.h
index 3e78e756a6..d7b2457c49 100644
--- a/src/widgets/widgets/qcombobox_p.h
+++ b/src/widgets/widgets/qcombobox_p.h
@@ -142,7 +142,7 @@ public:
         setAttribute(Qt::WA_NoMousePropagation);
     }
     QSize sizeHint() const override {
-        return QSize(20, style()->pixelMetric(QStyle::PM_MenuScrollerHeight));
+        return QSize(20, style()->pixelMetric(QStyle::PM_MenuScrollerHeight, nullptr, this));
     }
 
 protected:
diff --git a/src/widgets/widgets/qcommandlinkbutton.cpp b/src/widgets/widgets/qcommandlinkbutton.cpp
index 2b9258fd91..e9462ed229 100644
--- a/src/widgets/widgets/qcommandlinkbutton.cpp
+++ b/src/widgets/widgets/qcommandlinkbutton.cpp
@@ -208,7 +208,7 @@ bool QCommandLinkButtonPrivate::usingVistaStyle() const
     //### This is a hack to detect if we are indeed running Vista style themed and not in classic
     // When we add api to query for this, we should change this implementation to use it.
     return q->style()->inherits("QWindowsVistaStyle")
-        && !q->style()->pixelMetric(QStyle::PM_ButtonShiftHorizontal);
+        && q->style()->pixelMetric(QStyle::PM_ButtonShiftHorizontal, nullptr) == 0;
 }
 
 void QCommandLinkButtonPrivate::init()
@@ -355,8 +355,10 @@ void QCommandLinkButton::paintEvent(QPaintEvent *)
     option.icon = QIcon(); //we draw this ourselves
     QSize pixmapSize = icon().actualSize(iconSize());
 
-    int vOffset = isDown() ? style()->pixelMetric(QStyle::PM_ButtonShiftVertical) : 0;
-    int hOffset = isDown() ? style()->pixelMetric(QStyle::PM_ButtonShiftHorizontal) : 0;
+    const int vOffset = isDown()
+        ? style()->pixelMetric(QStyle::PM_ButtonShiftVertical, &option) : 0;
+    const int hOffset = isDown()
+        ? style()->pixelMetric(QStyle::PM_ButtonShiftHorizontal, &option) : 0;
 
     //Draw icon
     p.drawControl(QStyle::CE_PushButton, option);
diff --git a/src/widgets/widgets/qfocusframe.cpp b/src/widgets/widgets/qfocusframe.cpp
index 4d64c24db3..4e793d7a29 100644
--- a/src/widgets/widgets/qfocusframe.cpp
+++ b/src/widgets/widgets/qfocusframe.cpp
@@ -86,8 +86,10 @@ void QFocusFramePrivate::updateSize()
     if (!widget)
         return;
 
-    int vmargin = q->style()->pixelMetric(QStyle::PM_FocusFrameVMargin),
-        hmargin = q->style()->pixelMetric(QStyle::PM_FocusFrameHMargin);
+    QStyleOption opt;
+    q->initStyleOption(&opt);
+    int vmargin = q->style()->pixelMetric(QStyle::PM_FocusFrameVMargin, &opt),
+        hmargin = q->style()->pixelMetric(QStyle::PM_FocusFrameHMargin, &opt);
     QPoint pos(widget->x(), widget->y());
     if (q->parentWidget() != widget->parentWidget())
         pos = widget->parentWidget()->mapTo(q->parentWidget(), pos);
@@ -98,8 +100,6 @@ void QFocusFramePrivate::updateSize()
 
     q->setGeometry(geom);
     QStyleHintReturnMask mask;
-    QStyleOption opt;
-    q->initStyleOption(&opt);
     if (q->style()->styleHint(QStyle::SH_FocusFrame_Mask, &opt, q, &mask))
         q->setMask(mask.region);
 }
@@ -263,8 +263,8 @@ QFocusFrame::paintEvent(QPaintEvent *)
     QStylePainter p(this);
     QStyleOption option;
     initStyleOption(&option);
-    int vmargin = style()->pixelMetric(QStyle::PM_FocusFrameVMargin);
-    int hmargin = style()->pixelMetric(QStyle::PM_FocusFrameHMargin);
+    const int vmargin = style()->pixelMetric(QStyle::PM_FocusFrameVMargin, &option);
+    const int hmargin = style()->pixelMetric(QStyle::PM_FocusFrameHMargin, &option);
     QWidgetPrivate *wd = qt_widget_private(d->widget);
     QRect rect = wd->clipRect().adjusted(0, 0, hmargin*2, vmargin*2);
     p.setClipRect(rect);
diff --git a/src/widgets/widgets/qgroupbox.cpp b/src/widgets/widgets/qgroupbox.cpp
index 048fe42948..02a0bed325 100644
--- a/src/widgets/widgets/qgroupbox.cpp
+++ b/src/widgets/widgets/qgroupbox.cpp
@@ -491,9 +491,9 @@ QSize QGroupBox::minimumSizeHint() const
     int baseWidth = metrics.horizontalAdvance(d->title) + metrics.horizontalAdvance(QLatin1Char(' '));
     int baseHeight = metrics.height();
     if (d->checkable) {
-        baseWidth += style()->pixelMetric(QStyle::PM_IndicatorWidth);
-        baseWidth += style()->pixelMetric(QStyle::PM_CheckBoxLabelSpacing);
-        baseHeight = qMax(baseHeight, style()->pixelMetric(QStyle::PM_IndicatorHeight));
+        baseWidth += style()->pixelMetric(QStyle::PM_IndicatorWidth, &option);
+        baseWidth += style()->pixelMetric(QStyle::PM_CheckBoxLabelSpacing, &option);
+        baseHeight = qMax(baseHeight, style()->pixelMetric(QStyle::PM_IndicatorHeight, &option));
     }
 
     QSize size = style()->sizeFromContents(QStyle::CT_GroupBox, &option, QSize(baseWidth, baseHeight), this);
diff --git a/src/widgets/widgets/qlineedit.cpp b/src/widgets/widgets/qlineedit.cpp
index 19a95be0ff..675f09d283 100644
--- a/src/widgets/widgets/qlineedit.cpp
+++ b/src/widgets/widgets/qlineedit.cpp
@@ -2073,7 +2073,7 @@ void QLineEdit::paintEvent(QPaintEvent *)
     if (d->cursorVisible && !d->control->isReadOnly())
         flags |= QWidgetLineControl::DrawCursor;
 
-    d->control->setCursorWidth(style()->pixelMetric(QStyle::PM_TextCursorWidth));
+    d->control->setCursorWidth(style()->pixelMetric(QStyle::PM_TextCursorWidth, &panel));
     d->control->draw(&p, topLeft, r, flags);
 
 }
diff --git a/src/widgets/widgets/qmenu.cpp b/src/widgets/widgets/qmenu.cpp
index 701035fc32..abe4e485c0 100644
--- a/src/widgets/widgets/qmenu.cpp
+++ b/src/widgets/widgets/qmenu.cpp
@@ -2844,7 +2844,7 @@ void QMenu::paintEvent(QPaintEvent *e)
         frame.rect = rect();
         frame.palette = palette();
         frame.state = QStyle::State_None;
-        frame.lineWidth = style()->pixelMetric(QStyle::PM_MenuPanelWidth);
+        frame.lineWidth = style()->pixelMetric(QStyle::PM_MenuPanelWidth, &frame);
         frame.midLineWidth = 0;
         style()->drawPrimitive(QStyle::PE_FrameMenu, &frame, &p, this);
     }
diff --git a/src/widgets/widgets/qmenubar.cpp b/src/widgets/widgets/qmenubar.cpp
index ccd91ebee1..8724fa1a19 100644
--- a/src/widgets/widgets/qmenubar.cpp
+++ b/src/widgets/widgets/qmenubar.cpp
@@ -1014,7 +1014,7 @@ void QMenuBar::paintEvent(QPaintEvent *e)
         frame.rect = rect();
         frame.palette = palette();
         frame.state = QStyle::State_None;
-        frame.lineWidth = style()->pixelMetric(QStyle::PM_MenuBarPanelWidth);
+        frame.lineWidth = style()->pixelMetric(QStyle::PM_MenuBarPanelWidth, &frame);
         frame.midLineWidth = 0;
         style()->drawPrimitive(QStyle::PE_PanelMenuBar, &frame, &p, this);
     }
diff --git a/src/widgets/widgets/qtoolbarextension.cpp b/src/widgets/widgets/qtoolbarextension.cpp
index bbe7eddaa4..165c7f274b 100644
--- a/src/widgets/widgets/qtoolbarextension.cpp
+++ b/src/widgets/widgets/qtoolbarextension.cpp
@@ -81,7 +81,9 @@ void QToolBarExtension::paintEvent(QPaintEvent *)
 
 QSize QToolBarExtension::sizeHint() const
 {
-    int ext = style()->pixelMetric(QStyle::PM_ToolBarExtensionExtent);
+    QStyleOption opt;
+    opt.initFrom(this);
+    const int ext = style()->pixelMetric(QStyle::PM_ToolBarExtensionExtent, &opt);
     return QSize(ext, ext);
 }
 
diff --git a/src/widgets/widgets/qwidgettextcontrol.cpp b/src/widgets/widgets/qwidgettextcontrol.cpp
index edd4885450..45ab384036 100644
--- a/src/widgets/widgets/qwidgettextcontrol.cpp
+++ b/src/widgets/widgets/qwidgettextcontrol.cpp
@@ -2463,7 +2463,7 @@ void QWidgetTextControl::setCursorWidth(int width)
     Q_UNUSED(width);
 #else
     if (width == -1)
-        width = QApplication::style()->pixelMetric(QStyle::PM_TextCursorWidth);
+        width = QApplication::style()->pixelMetric(QStyle::PM_TextCursorWidth, nullptr);
     d->doc->documentLayout()->setProperty("cursorWidth", width);
 #endif
     d->repaintCursor();
diff --git a/tests/auto/network/socket/qtcpsocket/tst_qtcpsocket.cpp b/tests/auto/network/socket/qtcpsocket/tst_qtcpsocket.cpp
index b29db90da4..099aa5fb51 100644
--- a/tests/auto/network/socket/qtcpsocket/tst_qtcpsocket.cpp
+++ b/tests/auto/network/socket/qtcpsocket/tst_qtcpsocket.cpp
@@ -556,8 +556,14 @@ void tst_QTcpSocket::bind_data()
 
     // try to bind to a privileged ports
     // we should fail if we're not root (unless the ports are in use!)
+#ifdef Q_OS_DARWIN
+    // Alas, some quirk (starting from macOS 10.14): bind with port number 1
+    // fails with IPv4 (not IPv6 though, see below).
+    QTest::newRow("127.0.0.1:1") << "127.0.0.1" << 1 << false << QString();
+#else
     QTest::newRow("127.0.0.1:1") << "127.0.0.1" << 1 << QtNetworkSettings::canBindToLowPorts()
                                  << (QtNetworkSettings::canBindToLowPorts() ? "127.0.0.1" : QString());
+#endif // Q_OS_DARWIN
     if (testIpv6)
         QTest::newRow("[::]:1") << "::" << 1 << QtNetworkSettings::canBindToLowPorts()
                                 << (QtNetworkSettings::canBindToLowPorts() ? "::" : QString());
@@ -579,7 +585,7 @@ void tst_QTcpSocket::bind()
     QTcpSocket dummySocket;     // used only to "use up" a file descriptor
     dummySocket.bind();
 
-    QTcpSocket *socket = newSocket();
+    std::unique_ptr<QTcpSocket> socket(newSocket());
     quint16 boundPort;
     qintptr fd;
 
@@ -645,9 +651,24 @@ void tst_QTcpSocket::bind()
         QCOMPARE(acceptedSocket->peerPort(), boundPort);
         QCOMPARE(socket->localAddress(), remoteAddr);
         QCOMPARE(socket->socketDescriptor(), fd);
+#ifdef Q_OS_DARWIN
+        // Normally, we don't see this problem: macOS sometimes does not
+        // allow us to immediately re-use a port, thinking connection is
+        // still alive. With fixed port 1 (we testing starting from
+        // macOS 10.14), this problem shows, making the test flaky:
+        // we run this 'bind' with port 1 several times (different
+        // test cases) and the problem manifests itself as
+        // "The bound address is already in use, tried port 1".
+        QTestEventLoop cleanupHelper;
+        auto client = socket.get();
+        connect(client, &QTcpSocket::disconnected, [&cleanupHelper, client](){
+            client->close();
+            cleanupHelper.exitLoop();
+        });
+        acceptedSocket->close();
+        cleanupHelper.enterLoopMSecs(100);
+#endif // Q_OS_DARWIN
     }
-
-    delete socket;
 }
 
 //----------------------------------------------------------------------------------
diff --git a/tests/auto/widgets/itemviews/qtreeview/tst_qtreeview.cpp b/tests/auto/widgets/itemviews/qtreeview/tst_qtreeview.cpp
index 8396fd4ec7..7259fa1ab0 100644
--- a/tests/auto/widgets/itemviews/qtreeview/tst_qtreeview.cpp
+++ b/tests/auto/widgets/itemviews/qtreeview/tst_qtreeview.cpp
@@ -976,6 +976,7 @@ void tst_QTreeView::indexWidget()
     QStandardItemModel treeModel;
     initStandardTreeModel(&treeModel);
     view.setModel(&treeModel);
+    view.resize(300, 400);  // make sure the width of the view is larger than the widgets below
 
     QModelIndex index = view.model()->index(0, 0);
 
@@ -1004,6 +1005,7 @@ void tst_QTreeView::indexWidget()
 
     //now let's try to do that later when the widget is already shown
     view.show();
+    QVERIFY(QTest::qWaitForWindowExposed(&view));
     index = view.model()->index(1, 0);
     QVERIFY(!view.indexWidget(index));