[clangd] Move getBeginningOfIdentifier from ClangdUnit to SourceCode. Drop dependencies on ClangdUnit from some headers. NFC
llvm-svn: 370768
diff --git a/clang-tools-extra/clangd/SourceCode.cpp b/clang-tools-extra/clangd/SourceCode.cpp
index 0c52dcd..4291016 100644
--- a/clang-tools-extra/clangd/SourceCode.cpp
+++ b/clang-tools-extra/clangd/SourceCode.cpp
@@ -229,6 +229,39 @@
return halfOpenToRange(SM, CharSourceRange::getCharRange(TokLoc, End));
}
+SourceLocation getBeginningOfIdentifier(const Position &Pos,
+ const SourceManager &SM,
+ const LangOptions &LangOpts) {
+ FileID FID = SM.getMainFileID();
+ auto Offset = positionToOffset(SM.getBufferData(FID), Pos);
+ if (!Offset) {
+ log("getBeginningOfIdentifier: {0}", Offset.takeError());
+ return SourceLocation();
+ }
+
+ // GetBeginningOfToken(pos) is almost what we want, but does the wrong thing
+ // if the cursor is at the end of the identifier.
+ // Instead, we lex at GetBeginningOfToken(pos - 1). The cases are:
+ // 1) at the beginning of an identifier, we'll be looking at something
+ // that isn't an identifier.
+ // 2) at the middle or end of an identifier, we get the identifier.
+ // 3) anywhere outside an identifier, we'll get some non-identifier thing.
+ // We can't actually distinguish cases 1 and 3, but returning the original
+ // location is correct for both!
+ SourceLocation InputLoc = SM.getComposedLoc(FID, *Offset);
+ if (*Offset == 0) // Case 1 or 3.
+ return SM.getMacroArgExpandedLocation(InputLoc);
+ SourceLocation Before = SM.getComposedLoc(FID, *Offset - 1);
+
+ Before = Lexer::GetBeginningOfToken(Before, SM, LangOpts);
+ Token Tok;
+ if (Before.isValid() &&
+ !Lexer::getRawToken(Before, Tok, SM, LangOpts, false) &&
+ Tok.is(tok::raw_identifier))
+ return SM.getMacroArgExpandedLocation(Before); // Case 2.
+ return SM.getMacroArgExpandedLocation(InputLoc); // Case 1 or 3.
+}
+
bool isValidFileRange(const SourceManager &Mgr, SourceRange R) {
if (!R.getBegin().isValid() || !R.getEnd().isValid())
return false;