Introduce a new BufferResult class to act as the return type of

SourceManager's getBuffer() (and similar) operations. This abstract
can be used to force callers to cope with errors in getBuffer(), such
as missing files and changed files. Fix a bunch of callers to use the
new interface.

Add some very basic checks for file consistency (file size,
modification time) into ContentCache::getBuffer(), although these
checks don't help much until we've updated the main callers (e.g.,
SourceManager::getSpelling()).

llvm-svn: 98585

1 files changed, 11 insertions, 1 deletions

diff --git a/clang/lib/Rewrite/HTMLRewrite.cpp b/clang/lib/Rewrite/HTMLRewrite.cpp
index 342b0e6ef5e..cf1c779b3ea 100644
--- a/clang/lib/Rewrite/HTMLRewrite.cpp
+++ b/clang/lib/Rewrite/HTMLRewrite.cpp
@@ -43,8 +43,18 @@ void html::HighlightRange(Rewriter &R, SourceLocation B, SourceLocation E,
   // Include the whole end token in the range.
   EOffset += Lexer::MeasureTokenLength(E, R.getSourceMgr(), R.getLangOpts());
 
+  llvm::StringRef FileName;
+  std::string ErrorStr;
+  const char *BufferStart = SM.getBufferData(FID, FileName, ErrorStr).first;
+  if (!BufferStart) {
+    // FIXME: Add a diagnostic object somewhere?
+    fprintf(stderr, "error: cannot open file '%s': %s\n", 
+            FileName.str().c_str(), ErrorStr.c_str());
+    return;
+  }
+  
   HighlightRange(R.getEditBuffer(FID), BOffset, EOffset,
-                 SM.getBufferData(FID).first, StartTag, EndTag);
+                 BufferStart, StartTag, EndTag);
 }
 
 /// HighlightRange - This is the same as the above method, but takes