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//===--- Rewriter.cpp - Code rewriting interface --------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines the Rewriter class, which is used for code
// transformations.
//
//===----------------------------------------------------------------------===//
#include "clang/Rewrite/Rewriter.h"
#include "clang/AST/Stmt.h"
#include "clang/AST/Decl.h"
#include "clang/Lex/Lexer.h"
#include "clang/Basic/SourceManager.h"
#include "llvm/Support/raw_ostream.h"
using namespace clang;
llvm::raw_ostream &RewriteBuffer::write(llvm::raw_ostream &os) const {
// FIXME: eliminate the copy by writing out each chunk at a time
os << std::string(begin(), end());
return os;
}
void RewriteBuffer::RemoveText(unsigned OrigOffset, unsigned Size) {
// Nothing to remove, exit early.
if (Size == 0) return;
unsigned RealOffset = getMappedOffset(OrigOffset, true);
assert(RealOffset+Size < Buffer.size() && "Invalid location");
// Remove the dead characters.
Buffer.erase(RealOffset, Size);
// Add a delta so that future changes are offset correctly.
AddReplaceDelta(OrigOffset, -Size);
}
void RewriteBuffer::InsertText(unsigned OrigOffset, llvm::StringRef Str,
bool InsertAfter) {
// Nothing to insert, exit early.
if (Str.empty()) return;
unsigned RealOffset = getMappedOffset(OrigOffset, InsertAfter);
Buffer.insert(RealOffset, Str.begin(), Str.end());
// Add a delta so that future changes are offset correctly.
AddInsertDelta(OrigOffset, Str.size());
}
/// ReplaceText - This method replaces a range of characters in the input
/// buffer with a new string. This is effectively a combined "remove+insert"
/// operation.
void RewriteBuffer::ReplaceText(unsigned OrigOffset, unsigned OrigLength,
llvm::StringRef NewStr) {
unsigned RealOffset = getMappedOffset(OrigOffset, true);
Buffer.erase(RealOffset, OrigLength);
Buffer.insert(RealOffset, NewStr.begin(), NewStr.end());
if (OrigLength != NewStr.size())
AddReplaceDelta(OrigOffset, NewStr.size() - OrigLength);
}
//===----------------------------------------------------------------------===//
// Rewriter class
//===----------------------------------------------------------------------===//
/// getRangeSize - Return the size in bytes of the specified range if they
/// are in the same file. If not, this returns -1.
int Rewriter::getRangeSize(const CharSourceRange &Range) const {
if (!isRewritable(Range.getBegin()) ||
!isRewritable(Range.getEnd())) return -1;
FileID StartFileID, EndFileID;
unsigned StartOff, EndOff;
StartOff = getLocationOffsetAndFileID(Range.getBegin(), StartFileID);
EndOff = getLocationOffsetAndFileID(Range.getEnd(), EndFileID);
if (StartFileID != EndFileID)
return -1;
// If edits have been made to this buffer, the delta between the range may
// have changed.
std::map<FileID, RewriteBuffer>::const_iterator I =
RewriteBuffers.find(StartFileID);
if (I != RewriteBuffers.end()) {
const RewriteBuffer &RB = I->second;
EndOff = RB.getMappedOffset(EndOff, true);
StartOff = RB.getMappedOffset(StartOff);
}
// Adjust the end offset to the end of the last token, instead of being the
// start of the last token if this is a token range.
if (Range.isTokenRange())
EndOff += Lexer::MeasureTokenLength(Range.getEnd(), *SourceMgr, *LangOpts);
return EndOff-StartOff;
}
int Rewriter::getRangeSize(SourceRange Range) const {
return getRangeSize(CharSourceRange::getTokenRange(Range));
}
/// getRewrittenText - Return the rewritten form of the text in the specified
/// range. If the start or end of the range was unrewritable or if they are
/// in different buffers, this returns an empty string.
///
/// Note that this method is not particularly efficient.
///
std::string Rewriter::getRewrittenText(SourceRange Range) const {
if (!isRewritable(Range.getBegin()) ||
!isRewritable(Range.getEnd()))
return "";
FileID StartFileID, EndFileID;
unsigned StartOff, EndOff;
StartOff = getLocationOffsetAndFileID(Range.getBegin(), StartFileID);
EndOff = getLocationOffsetAndFileID(Range.getEnd(), EndFileID);
if (StartFileID != EndFileID)
return ""; // Start and end in different buffers.
// If edits have been made to this buffer, the delta between the range may
// have changed.
std::map<FileID, RewriteBuffer>::const_iterator I =
RewriteBuffers.find(StartFileID);
if (I == RewriteBuffers.end()) {
// If the buffer hasn't been rewritten, just return the text from the input.
const char *Ptr = SourceMgr->getCharacterData(Range.getBegin());
// Adjust the end offset to the end of the last token, instead of being the
// start of the last token.
EndOff += Lexer::MeasureTokenLength(Range.getEnd(), *SourceMgr, *LangOpts);
return std::string(Ptr, Ptr+EndOff-StartOff);
}
const RewriteBuffer &RB = I->second;
EndOff = RB.getMappedOffset(EndOff, true);
StartOff = RB.getMappedOffset(StartOff);
// Adjust the end offset to the end of the last token, instead of being the
// start of the last token.
EndOff += Lexer::MeasureTokenLength(Range.getEnd(), *SourceMgr, *LangOpts);
// Advance the iterators to the right spot, yay for linear time algorithms.
RewriteBuffer::iterator Start = RB.begin();
std::advance(Start, StartOff);
RewriteBuffer::iterator End = Start;
std::advance(End, EndOff-StartOff);
return std::string(Start, End);
}
unsigned Rewriter::getLocationOffsetAndFileID(SourceLocation Loc,
FileID &FID) const {
assert(Loc.isValid() && "Invalid location");
std::pair<FileID,unsigned> V = SourceMgr->getDecomposedLoc(Loc);
FID = V.first;
return V.second;
}
/// getEditBuffer - Get or create a RewriteBuffer for the specified FileID.
///
RewriteBuffer &Rewriter::getEditBuffer(FileID FID) {
std::map<FileID, RewriteBuffer>::iterator I =
RewriteBuffers.lower_bound(FID);
if (I != RewriteBuffers.end() && I->first == FID)
return I->second;
I = RewriteBuffers.insert(I, std::make_pair(FID, RewriteBuffer()));
llvm::StringRef MB = SourceMgr->getBufferData(FID);
I->second.Initialize(MB.begin(), MB.end());
return I->second;
}
/// InsertText - Insert the specified string at the specified location in the
/// original buffer.
bool Rewriter::InsertText(SourceLocation Loc, llvm::StringRef Str,
bool InsertAfter) {
if (!isRewritable(Loc)) return true;
FileID FID;
unsigned StartOffs = getLocationOffsetAndFileID(Loc, FID);
getEditBuffer(FID).InsertText(StartOffs, Str, InsertAfter);
return false;
}
/// RemoveText - Remove the specified text region.
bool Rewriter::RemoveText(SourceLocation Start, unsigned Length) {
if (!isRewritable(Start)) return true;
FileID FID;
unsigned StartOffs = getLocationOffsetAndFileID(Start, FID);
getEditBuffer(FID).RemoveText(StartOffs, Length);
return false;
}
/// ReplaceText - This method replaces a range of characters in the input
/// buffer with a new string. This is effectively a combined "remove/insert"
/// operation.
bool Rewriter::ReplaceText(SourceLocation Start, unsigned OrigLength,
llvm::StringRef NewStr) {
if (!isRewritable(Start)) return true;
FileID StartFileID;
unsigned StartOffs = getLocationOffsetAndFileID(Start, StartFileID);
getEditBuffer(StartFileID).ReplaceText(StartOffs, OrigLength, NewStr);
return false;
}
/// ReplaceStmt - This replaces a Stmt/Expr with another, using the pretty
/// printer to generate the replacement code. This returns true if the input
/// could not be rewritten, or false if successful.
bool Rewriter::ReplaceStmt(Stmt *From, Stmt *To) {
// Measaure the old text.
int Size = getRangeSize(From->getSourceRange());
if (Size == -1)
return true;
// Get the new text.
std::string SStr;
llvm::raw_string_ostream S(SStr);
To->printPretty(S, 0, PrintingPolicy(*LangOpts));
const std::string &Str = S.str();
ReplaceText(From->getLocStart(), Size, Str);
return false;
}