[backported/clang-7][libclang] Optionally add code completion results for arrow instead of dot

--------------------------------------------------------------------------
* https://reviews.llvm.org/D46862
--------------------------------------------------------------------------

Follow up for https://reviews.llvm.org/D41537 -
libclang part is extracted into this review

Change-Id: Ib166eb7b8675be605c81330df0c5f342942815ce
Reviewed-by: Ivan Donchevskii <ivan.donchevskii@qt.io>

3 files changed, 92 insertions, 4 deletions

diff --git a/tools/libclang/CIndex.cpp b/tools/libclang/CIndex.cpp
index 884206d9d1..c44c72e2ed 100644
--- a/tools/libclang/CIndex.cpp
+++ b/tools/libclang/CIndex.cpp
@@ -6642,6 +6642,42 @@ static void getTokens(ASTUnit *CXXUnit, SourceRange Range,
   } while (Lex.getBufferLocation() < EffectiveBufferEnd);
 }
 
+CXToken *clang_getToken(CXTranslationUnit TU, CXSourceLocation Location) {
+  LOG_FUNC_SECTION {
+    *Log << TU << ' ' << Location;
+  }
+
+  if (isNotUsableTU(TU)) {
+    LOG_BAD_TU(TU);
+    return nullptr;
+  }
+
+  ASTUnit *CXXUnit = cxtu::getASTUnit(TU);
+  if (!CXXUnit)
+    return nullptr;
+
+  SourceLocation Begin = cxloc::translateSourceLocation(Location);
+  if (Begin.isInvalid())
+    return nullptr;
+  SourceManager &SM = CXXUnit->getSourceManager();
+  std::pair<FileID, unsigned> DecomposedEnd = SM.getDecomposedLoc(Begin);
+  DecomposedEnd.second += Lexer::MeasureTokenLength(Begin, SM, CXXUnit->getLangOpts());
+
+  SourceLocation End = SM.getComposedLoc(DecomposedEnd.first, DecomposedEnd.second);
+
+  SmallVector<CXToken, 32> CXTokens;
+  getTokens(CXXUnit, SourceRange(Begin, End), CXTokens);
+
+  if (CXTokens.empty())
+    return nullptr;
+
+  CXTokens.resize(1);
+  CXToken *Token = (CXToken *)malloc(sizeof(CXToken));
+
+  memmove(Token, CXTokens.data(), sizeof(CXToken));
+  return Token;
+}
+
 void clang_tokenize(CXTranslationUnit TU, CXSourceRange Range,
                     CXToken **Tokens, unsigned *NumTokens) {
   LOG_FUNC_SECTION {
diff --git a/tools/libclang/CIndexCodeCompletion.cpp b/tools/libclang/CIndexCodeCompletion.cpp
index d4af0870c0..32fc7325f0 100644
--- a/tools/libclang/CIndexCodeCompletion.cpp
+++ b/tools/libclang/CIndexCodeCompletion.cpp
@@ -16,6 +16,7 @@
 #include "CIndexDiagnostic.h"
 #include "CLog.h"
 #include "CXCursor.h"
+#include "CXSourceLocation.h"
 #include "CXString.h"
 #include "CXTranslationUnit.h"
 #include "clang/AST/Decl.h"
@@ -302,10 +303,53 @@ struct AllocatedCXCodeCompleteResults : public CXCodeCompleteResults {
   /// \brief A string containing the Objective-C selector entered thus far for a
   /// message send.
   std::string Selector;
+
+  /// \brief Vector of fix-its for each completion result that *must* be applied
+  /// before that result for the corresponding completion item.
+  std::vector<std::vector<FixItHint>> FixItsVector;
 };
 
 } // end anonymous namespace
 
+unsigned clang_getCompletionNumFixIts(CXCodeCompleteResults *results,
+                                      unsigned completion_index) {
+  AllocatedCXCodeCompleteResults *allocated_results = (AllocatedCXCodeCompleteResults *)results;
+
+  if (!allocated_results || allocated_results->FixItsVector.size() <= completion_index)
+    return 0;
+
+  return static_cast<unsigned>(allocated_results->FixItsVector[completion_index].size());
+}
+
+CXString clang_getCompletionFixIt(CXCodeCompleteResults *results,
+                                  unsigned completion_index,
+                                  unsigned fixit_index,
+                                  CXSourceRange *replacement_range) {
+  AllocatedCXCodeCompleteResults *allocated_results = (AllocatedCXCodeCompleteResults *)results;
+
+  if (!allocated_results || allocated_results->FixItsVector.size() <= completion_index) {
+    if (replacement_range)
+      *replacement_range = clang_getNullRange();
+    return cxstring::createNull();
+  }
+
+  ArrayRef<FixItHint> FixIts = allocated_results->FixItsVector[completion_index];
+  if (FixIts.size() <= fixit_index) {
+    if (replacement_range)
+      *replacement_range = clang_getNullRange();
+    return cxstring::createNull();
+  }
+
+  const FixItHint &FixIt = FixIts[fixit_index];
+  if (replacement_range) {
+    *replacement_range = cxloc::translateSourceRange(
+        *allocated_results->SourceMgr, allocated_results->LangOpts,
+        FixIt.RemoveRange);
+  }
+
+  return cxstring::createRef(FixIt.CodeToInsert.c_str());
+}
+
 /// \brief Tracks the number of code-completion result objects that are 
 /// currently active.
 ///
@@ -531,8 +575,10 @@ namespace {
                                     CodeCompletionResult *Results,
                                     unsigned NumResults) override {
       StoredResults.reserve(StoredResults.size() + NumResults);
+      if (includeFixIts())
+        AllocatedResults.FixItsVector.reserve(NumResults);
       for (unsigned I = 0; I != NumResults; ++I) {
-        CodeCompletionString *StoredCompletion        
+        CodeCompletionString *StoredCompletion
           = Results[I].CreateCodeCompletionString(S, Context, getAllocator(),
                                                   getCodeCompletionTUInfo(),
                                                   includeBriefComments());
@@ -541,8 +587,10 @@ namespace {
         R.CursorKind = Results[I].CursorKind;
         R.CompletionString = StoredCompletion;
         StoredResults.push_back(R);
+        if (includeFixIts())
+          AllocatedResults.FixItsVector.emplace_back(std::move(Results[I].FixIts));
       }
-      
+
       enum CodeCompletionContext::Kind contextKind = Context.getKind();
       
       AllocatedResults.ContextKind = contextKind;
@@ -643,13 +691,13 @@ clang_codeCompleteAt_Impl(CXTranslationUnit TU, const char *complete_filename,
                           ArrayRef<CXUnsavedFile> unsaved_files,
                           unsigned options) {
   bool IncludeBriefComments = options & CXCodeComplete_IncludeBriefComments;
+  bool IncludeFixIts = options & CXCodeComplete_IncludeCompletionsWithFixIts;
 
 #ifdef UDP_CODE_COMPLETION_LOGGER
 #ifdef UDP_CODE_COMPLETION_LOGGER_PORT
   const llvm::TimeRecord &StartTime =  llvm::TimeRecord::getCurrentTime();
 #endif
 #endif
-
   bool EnableLogging = getenv("LIBCLANG_CODE_COMPLETION_LOGGING") != nullptr;
 
   if (cxtu::isNotUsableTU(TU)) {
@@ -689,6 +737,7 @@ clang_codeCompleteAt_Impl(CXTranslationUnit TU, const char *complete_filename,
   // Create a code-completion consumer to capture the results.
   CodeCompleteOptions Opts;
   Opts.IncludeBriefComments = IncludeBriefComments;
+  Opts.IncludeFixIts = IncludeFixIts;
   CaptureCompletionResults Capture(Opts, *Results, &TU);
 
   // Perform completion.
@@ -962,7 +1011,7 @@ namespace {
         = (CodeCompletionString *)XR.CompletionString;
       CodeCompletionString *Y
         = (CodeCompletionString *)YR.CompletionString;
-      
+
       SmallString<256> XBuffer;
       StringRef XText = GetTypedName(X, XBuffer);
       SmallString<256> YBuffer;
diff --git a/tools/libclang/libclang.exports b/tools/libclang/libclang.exports
index 67e4b4334b..8deca1cb50 100644
--- a/tools/libclang/libclang.exports
+++ b/tools/libclang/libclang.exports
@@ -170,6 +170,8 @@ clang_getCompletionBriefComment
 clang_getCompletionChunkCompletionString
 clang_getCompletionChunkKind
 clang_getCompletionChunkText
+clang_getCompletionNumFixIts
+clang_getCompletionFixIt
 clang_getCompletionNumAnnotations
 clang_getCompletionParent
 clang_getCompletionPriority
@@ -259,6 +261,7 @@ clang_getSpecializedCursorTemplate
 clang_getSpellingLocation
 clang_getTUResourceUsageName
 clang_getTemplateCursorKind
+clang_getToken
 clang_getTokenExtent
 clang_getTokenKind
 clang_getTokenLocation