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authorEskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@qt.io>2019-11-11 15:10:08 +0100
committerEskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@qt.io>2020-03-04 08:28:04 +0100
commitfb2f42b6044fe4673e71f3d12082b53c9f3182cd (patch)
treed2f579c0362be1def50d957bc4e46eb27ea6198a /src/3rdparty/harfbuzz-ng/src/hb-sanitize.hh
parent4724dfff627f3cd3754f5d4a827c6b6790a89955 (diff)
Update to Harfbuzz 2.6.4
Quite a big change since it has been several years since the last update. This drops the Harfbuzz source on top of the existing code in Qt, and does the following additional changes: 1. Deletes old source files that have been removed upstream (everything named foo-private.hh is now renamed to just foo.hh for instance). 2. Added a header guard to config.h because it may be double-included. 3. Implement a memory barrier needed by hb-atomic.hh. 4. Changed the signature of hb_atomic_int_impl_add() to take a pointer to match new upstream. 5. Updated .pro file to include new files and removed old. 6. Updated qt_attribution.json 7. No longer disable deprecated APIs since hb_ot_tags_from_script() is now deprecated and is used from Qt code. 8. Updated and applied the patch in patches/ for CoreText. 9. Updated tst_qtextscriptengine::thaiWithZWJ() according to changes in Harfbuzz and disabled it for system-harfbuzz, since this may be an older version of harfbuzz depending on the system. Fixes: QTBUG-79606 Change-Id: I3f057a43ff44ee416628b75ef12fb1a221f31910 Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org> Reviewed-by: Lars Knoll <lars.knoll@qt.io>
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+/*
+ * Copyright © 2007,2008,2009,2010 Red Hat, Inc.
+ * Copyright © 2012,2018 Google, Inc.
+ *
+ * This is part of HarfBuzz, a text shaping library.
+ *
+ * Permission is hereby granted, without written agreement and without
+ * license or royalty fees, to use, copy, modify, and distribute this
+ * software and its documentation for any purpose, provided that the
+ * above copyright notice and the following two paragraphs appear in
+ * all copies of this software.
+ *
+ * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
+ * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
+ * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
+ * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
+ * DAMAGE.
+ *
+ * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
+ * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
+ * FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
+ * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
+ * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
+ *
+ * Red Hat Author(s): Behdad Esfahbod
+ * Google Author(s): Behdad Esfahbod
+ */
+
+#ifndef HB_SANITIZE_HH
+#define HB_SANITIZE_HH
+
+#include "hb.hh"
+#include "hb-blob.hh"
+#include "hb-dispatch.hh"
+
+
+/*
+ * Sanitize
+ *
+ *
+ * === Introduction ===
+ *
+ * The sanitize machinery is at the core of our zero-cost font loading. We
+ * mmap() font file into memory and create a blob out of it. Font subtables
+ * are returned as a readonly sub-blob of the main font blob. These table
+ * blobs are then sanitized before use, to ensure invalid memory access does
+ * not happen. The toplevel sanitize API use is like, eg. to load the 'head'
+ * table:
+ *
+ * hb_blob_t *head_blob = hb_sanitize_context_t ().reference_table<OT::head> (face);
+ *
+ * The blob then can be converted to a head table struct with:
+ *
+ * const head *head_table = head_blob->as<head> ();
+ *
+ * What the reference_table does is, to call hb_face_reference_table() to load
+ * the table blob, sanitize it and return either the sanitized blob, or empty
+ * blob if sanitization failed. The blob->as() function returns the null
+ * object of its template type argument if the blob is empty. Otherwise, it
+ * just casts the blob contents to the desired type.
+ *
+ * Sanitizing a blob of data with a type T works as follows (with minor
+ * simplification):
+ *
+ * - Cast blob content to T*, call sanitize() method of it,
+ * - If sanitize succeeded, return blob.
+ * - Otherwise, if blob is not writable, try making it writable,
+ * or copy if cannot be made writable in-place,
+ * - Call sanitize() again. Return blob if sanitize succeeded.
+ * - Return empty blob otherwise.
+ *
+ *
+ * === The sanitize() contract ===
+ *
+ * The sanitize() method of each object type shall return true if it's safe to
+ * call other methods of the object, and false otherwise.
+ *
+ * Note that what sanitize() checks for might align with what the specification
+ * describes as valid table data, but does not have to be. In particular, we
+ * do NOT want to be pedantic and concern ourselves with validity checks that
+ * are irrelevant to our use of the table. On the contrary, we want to be
+ * lenient with error handling and accept invalid data to the extent that it
+ * does not impose extra burden on us.
+ *
+ * Based on the sanitize contract, one can see that what we check for depends
+ * on how we use the data in other table methods. Ie. if other table methods
+ * assume that offsets do NOT point out of the table data block, then that's
+ * something sanitize() must check for (GSUB/GPOS/GDEF/etc work this way). On
+ * the other hand, if other methods do such checks themselves, then sanitize()
+ * does not have to bother with them (glyf/local work this way). The choice
+ * depends on the table structure and sanitize() performance. For example, to
+ * check glyf/loca offsets in sanitize() would cost O(num-glyphs). We try hard
+ * to avoid such costs during font loading. By postponing such checks to the
+ * actual glyph loading, we reduce the sanitize cost to O(1) and total runtime
+ * cost to O(used-glyphs). As such, this is preferred.
+ *
+ * The same argument can be made re GSUB/GPOS/GDEF, but there, the table
+ * structure is so complicated that by checking all offsets at sanitize() time,
+ * we make the code much simpler in other methods, as offsets and referenced
+ * objects do not need to be validated at each use site.
+ */
+
+/* This limits sanitizing time on really broken fonts. */
+#ifndef HB_SANITIZE_MAX_EDITS
+#define HB_SANITIZE_MAX_EDITS 32
+#endif
+#ifndef HB_SANITIZE_MAX_OPS_FACTOR
+#define HB_SANITIZE_MAX_OPS_FACTOR 8
+#endif
+#ifndef HB_SANITIZE_MAX_OPS_MIN
+#define HB_SANITIZE_MAX_OPS_MIN 16384
+#endif
+#ifndef HB_SANITIZE_MAX_OPS_MAX
+#define HB_SANITIZE_MAX_OPS_MAX 0x3FFFFFFF
+#endif
+
+struct hb_sanitize_context_t :
+ hb_dispatch_context_t<hb_sanitize_context_t, bool, HB_DEBUG_SANITIZE>
+{
+ hb_sanitize_context_t () :
+ debug_depth (0),
+ start (nullptr), end (nullptr),
+ max_ops (0),
+ writable (false), edit_count (0),
+ blob (nullptr),
+ num_glyphs (65536),
+ num_glyphs_set (false) {}
+
+ const char *get_name () { return "SANITIZE"; }
+ template <typename T, typename F>
+ bool may_dispatch (const T *obj HB_UNUSED, const F *format)
+ { return format->sanitize (this); }
+ static return_t default_return_value () { return true; }
+ static return_t no_dispatch_return_value () { return false; }
+ bool stop_sublookup_iteration (const return_t r) const { return !r; }
+
+ private:
+ template <typename T, typename ...Ts> auto
+ _dispatch (const T &obj, hb_priority<1>, Ts&&... ds) HB_AUTO_RETURN
+ ( obj.sanitize (this, hb_forward<Ts> (ds)...) )
+ template <typename T, typename ...Ts> auto
+ _dispatch (const T &obj, hb_priority<0>, Ts&&... ds) HB_AUTO_RETURN
+ ( obj.dispatch (this, hb_forward<Ts> (ds)...) )
+ public:
+ template <typename T, typename ...Ts> auto
+ dispatch (const T &obj, Ts&&... ds) HB_AUTO_RETURN
+ ( _dispatch (obj, hb_prioritize, hb_forward<Ts> (ds)...) )
+
+
+ void init (hb_blob_t *b)
+ {
+ this->blob = hb_blob_reference (b);
+ this->writable = false;
+ }
+
+ void set_num_glyphs (unsigned int num_glyphs_)
+ {
+ num_glyphs = num_glyphs_;
+ num_glyphs_set = true;
+ }
+ unsigned int get_num_glyphs () { return num_glyphs; }
+
+ void set_max_ops (int max_ops_) { max_ops = max_ops_; }
+
+ template <typename T>
+ void set_object (const T *obj)
+ {
+ reset_object ();
+
+ if (!obj) return;
+
+ const char *obj_start = (const char *) obj;
+ if (unlikely (obj_start < this->start || this->end <= obj_start))
+ this->start = this->end = nullptr;
+ else
+ {
+ this->start = obj_start;
+ this->end = obj_start + hb_min (size_t (this->end - obj_start), obj->get_size ());
+ }
+ }
+
+ void reset_object ()
+ {
+ this->start = this->blob->data;
+ this->end = this->start + this->blob->length;
+ assert (this->start <= this->end); /* Must not overflow. */
+ }
+
+ void start_processing ()
+ {
+ reset_object ();
+ this->max_ops = hb_max ((unsigned int) (this->end - this->start) * HB_SANITIZE_MAX_OPS_FACTOR,
+ (unsigned) HB_SANITIZE_MAX_OPS_MIN);
+ this->edit_count = 0;
+ this->debug_depth = 0;
+
+ DEBUG_MSG_LEVEL (SANITIZE, start, 0, +1,
+ "start [%p..%p] (%lu bytes)",
+ this->start, this->end,
+ (unsigned long) (this->end - this->start));
+ }
+
+ void end_processing ()
+ {
+ DEBUG_MSG_LEVEL (SANITIZE, this->start, 0, -1,
+ "end [%p..%p] %u edit requests",
+ this->start, this->end, this->edit_count);
+
+ hb_blob_destroy (this->blob);
+ this->blob = nullptr;
+ this->start = this->end = nullptr;
+ }
+
+ unsigned get_edit_count () { return edit_count; }
+
+ bool check_range (const void *base,
+ unsigned int len) const
+ {
+ const char *p = (const char *) base;
+ bool ok = !len ||
+ (this->start <= p &&
+ p <= this->end &&
+ (unsigned int) (this->end - p) >= len &&
+ this->max_ops-- > 0);
+
+ DEBUG_MSG_LEVEL (SANITIZE, p, this->debug_depth+1, 0,
+ "check_range [%p..%p]"
+ " (%d bytes) in [%p..%p] -> %s",
+ p, p + len, len,
+ this->start, this->end,
+ ok ? "OK" : "OUT-OF-RANGE");
+
+ return likely (ok);
+ }
+
+ template <typename T>
+ bool check_range (const T *base,
+ unsigned int a,
+ unsigned int b) const
+ {
+ return !hb_unsigned_mul_overflows (a, b) &&
+ this->check_range (base, a * b);
+ }
+
+ template <typename T>
+ bool check_range (const T *base,
+ unsigned int a,
+ unsigned int b,
+ unsigned int c) const
+ {
+ return !hb_unsigned_mul_overflows (a, b) &&
+ this->check_range (base, a * b, c);
+ }
+
+ template <typename T>
+ bool check_array (const T *base, unsigned int len) const
+ {
+ return this->check_range (base, len, hb_static_size (T));
+ }
+
+ template <typename T>
+ bool check_array (const T *base,
+ unsigned int a,
+ unsigned int b) const
+ {
+ return this->check_range (base, a, b, hb_static_size (T));
+ }
+
+ template <typename Type>
+ bool check_struct (const Type *obj) const
+ { return likely (this->check_range (obj, obj->min_size)); }
+
+ bool may_edit (const void *base, unsigned int len)
+ {
+ if (this->edit_count >= HB_SANITIZE_MAX_EDITS)
+ return false;
+
+ const char *p = (const char *) base;
+ this->edit_count++;
+
+ DEBUG_MSG_LEVEL (SANITIZE, p, this->debug_depth+1, 0,
+ "may_edit(%u) [%p..%p] (%d bytes) in [%p..%p] -> %s",
+ this->edit_count,
+ p, p + len, len,
+ this->start, this->end,
+ this->writable ? "GRANTED" : "DENIED");
+
+ return this->writable;
+ }
+
+ template <typename Type, typename ValueType>
+ bool try_set (const Type *obj, const ValueType &v)
+ {
+ if (this->may_edit (obj, hb_static_size (Type)))
+ {
+ * const_cast<Type *> (obj) = v;
+ return true;
+ }
+ return false;
+ }
+
+ template <typename Type>
+ hb_blob_t *sanitize_blob (hb_blob_t *blob)
+ {
+ bool sane;
+
+ init (blob);
+
+ retry:
+ DEBUG_MSG_FUNC (SANITIZE, start, "start");
+
+ start_processing ();
+
+ if (unlikely (!start))
+ {
+ end_processing ();
+ return blob;
+ }
+
+ Type *t = reinterpret_cast<Type *> (const_cast<char *> (start));
+
+ sane = t->sanitize (this);
+ if (sane)
+ {
+ if (edit_count)
+ {
+ DEBUG_MSG_FUNC (SANITIZE, start, "passed first round with %d edits; going for second round", edit_count);
+
+ /* sanitize again to ensure no toe-stepping */
+ edit_count = 0;
+ sane = t->sanitize (this);
+ if (edit_count) {
+ DEBUG_MSG_FUNC (SANITIZE, start, "requested %d edits in second round; FAILLING", edit_count);
+ sane = false;
+ }
+ }
+ }
+ else
+ {
+ if (edit_count && !writable) {
+ start = hb_blob_get_data_writable (blob, nullptr);
+ end = start + blob->length;
+
+ if (start)
+ {
+ writable = true;
+ /* ok, we made it writable by relocating. try again */
+ DEBUG_MSG_FUNC (SANITIZE, start, "retry");
+ goto retry;
+ }
+ }
+ }
+
+ end_processing ();
+
+ DEBUG_MSG_FUNC (SANITIZE, start, sane ? "PASSED" : "FAILED");
+ if (sane)
+ {
+ hb_blob_make_immutable (blob);
+ return blob;
+ }
+ else
+ {
+ hb_blob_destroy (blob);
+ return hb_blob_get_empty ();
+ }
+ }
+
+ template <typename Type>
+ hb_blob_t *reference_table (const hb_face_t *face, hb_tag_t tableTag = Type::tableTag)
+ {
+ if (!num_glyphs_set)
+ set_num_glyphs (hb_face_get_glyph_count (face));
+ return sanitize_blob<Type> (hb_face_reference_table (face, tableTag));
+ }
+
+ mutable unsigned int debug_depth;
+ const char *start, *end;
+ mutable int max_ops;
+ private:
+ bool writable;
+ unsigned int edit_count;
+ hb_blob_t *blob;
+ unsigned int num_glyphs;
+ bool num_glyphs_set;
+};
+
+struct hb_sanitize_with_object_t
+{
+ template <typename T>
+ hb_sanitize_with_object_t (hb_sanitize_context_t *c, const T& obj) : c (c)
+ { c->set_object (obj); }
+ ~hb_sanitize_with_object_t ()
+ { c->reset_object (); }
+
+ private:
+ hb_sanitize_context_t *c;
+};
+
+
+#endif /* HB_SANITIZE_HH */
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