[CodeComplete] Add completions for filenames in #include directives.

Summary:
The dir component ("somedir" in #include <somedir/fo...>) is considered fixed.
We append "foo" to each directory on the include path, and then list its files.

Completions are of the forms:
 #include <somedir/fo^
                   foo.h>
                   fox/

The filter is set to the filename part ("fo"), so fuzzy matching can be
applied to the filename only.

No fancy scoring/priorities are set, and no information is added to
CodeCompleteResult to make smart scoring possible. Could be in future.

Reviewers: ilya-biryukov

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D52076

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@342449 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 14 insertions, 0 deletions

diff --git a/include/clang/Lex/CodeCompletionHandler.h b/include/clang/Lex/CodeCompletionHandler.h
index 87089fd7d5..6b368c74c5 100644
--- a/include/clang/Lex/CodeCompletionHandler.h
+++ b/include/clang/Lex/CodeCompletionHandler.h
@@ -14,6 +14,8 @@
 #ifndef LLVM_CLANG_LEX_CODECOMPLETIONHANDLER_H
 #define LLVM_CLANG_LEX_CODECOMPLETIONHANDLER_H
 
+#include "llvm/ADT/StringRef.h"
+
 namespace clang {
 
 class IdentifierInfo;
@@ -60,6 +62,11 @@ public:
                                          MacroInfo *MacroInfo,
                                          unsigned ArgumentIndex) { }
 
+  /// Callback invoked when performing code completion inside the filename
+  /// part of an #include directive. (Also #import, #include_next, etc).
+  /// \p Dir is the directory relative to the include path, e.g. "a" for <a/b.
+  virtual void CodeCompleteIncludedFile(llvm::StringRef Dir, bool IsAngled) {}
+
   /// Callback invoked when performing code completion in a part of the
   /// file where we expect natural language, e.g., a comment, string, or
   /// \#error directive.
diff --git a/include/clang/Lex/Lexer.h b/include/clang/Lex/Lexer.h
index 7af9d43b3f..a9b10b6273 100644
--- a/include/clang/Lex/Lexer.h
+++ b/include/clang/Lex/Lexer.h
@@ -711,6 +711,9 @@ private:
 
   bool isHexaLiteral(const char *Start, const LangOptions &LangOpts);
 
+  void codeCompleteIncludedFile(const char *PathStart,
+                                const char *CompletionPoint, bool IsAngled);
+
   /// Read a universal character name.
   ///
   /// \param StartPtr The position in the source buffer after the initial '\'.
diff --git a/include/clang/Lex/Preprocessor.h b/include/clang/Lex/Preprocessor.h
index 02ea80aa3f..75910011d0 100644
--- a/include/clang/Lex/Preprocessor.h
+++ b/include/clang/Lex/Preprocessor.h
@@ -1128,6 +1128,10 @@ public:
     CodeComplete = nullptr;
   }
 
+  /// Hook used by the lexer to invoke the "included file" code
+  /// completion point.
+  void CodeCompleteIncludedFile(llvm::StringRef Dir, bool IsAngled);
+
   /// Hook used by the lexer to invoke the "natural language" code
   /// completion point.
   void CodeCompleteNaturalLanguage();