Rewriter: Output RewriteRope contents efficiently
This avoids allocation of temporary std::strings for file contents, instead
writing chunks directly to the output stream.
The old character-based B-tree iterator remains intact for the time being.
llvm-svn: 196119
GitOrigin-RevId: d505d403604a5a253f4dc3adcf1c0fcb343aa62c
diff --git a/include/clang/Rewrite/Core/RewriteRope.h b/include/clang/Rewrite/Core/RewriteRope.h
index a5192ef..5167c50 100644
--- a/include/clang/Rewrite/Core/RewriteRope.h
+++ b/include/clang/Rewrite/Core/RewriteRope.h
@@ -14,6 +14,7 @@
#ifndef LLVM_CLANG_REWRITEROPE_H
#define LLVM_CLANG_REWRITEROPE_H
+#include "llvm/ADT/StringRef.h"
#include "llvm/Support/Compiler.h"
#include <cassert>
#include <cstddef>
@@ -144,7 +145,11 @@
inline RopePieceBTreeIterator operator++(int) { // Postincrement
RopePieceBTreeIterator tmp = *this; ++*this; return tmp;
}
- private:
+
+ llvm::StringRef piece() const {
+ return llvm::StringRef(&(*CurPiece)[0], CurPiece->size());
+ }
+
void MoveToNextPiece();
};
diff --git a/lib/Rewrite/Core/Rewriter.cpp b/lib/Rewrite/Core/Rewriter.cpp
index afb1080..51af839 100644
--- a/lib/Rewrite/Core/Rewriter.cpp
+++ b/lib/Rewrite/Core/Rewriter.cpp
@@ -26,8 +26,11 @@
using namespace clang;
raw_ostream &RewriteBuffer::write(raw_ostream &os) const {
- // FIXME: eliminate the copy by writing out each chunk at a time
- os << std::string(begin(), end());
+ // Walk RewriteRope chunks efficiently using MoveToNextPiece() instead of the
+ // character iterator.
+ for (RopePieceBTreeIterator I = begin(), E = end(); I != E;
+ I.MoveToNextPiece())
+ os << I.piece();
return os;
}
