//===- Rewriter.cpp - Code rewriting interface ----------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file defines the Rewriter class, which is used for code
// transformations.
//
//===----------------------------------------------------------------------===//
#include "clang/Rewrite/Core/Rewriter.h"
#include "clang/Basic/Diagnostic.h"
#include "clang/Basic/DiagnosticIDs.h"
#include "clang/Basic/FileManager.h"
#include "clang/Basic/SourceLocation.h"
#include "clang/Basic/SourceManager.h"
#include "clang/Lex/Lexer.h"
#include "clang/Rewrite/Core/RewriteBuffer.h"
#include "clang/Rewrite/Core/RewriteRope.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/Support/FileSystem.h"
#include "llvm/Support/raw_ostream.h"
#include <cassert>
#include <iterator>
#include <map>
#include <memory>
#include <system_error>
#include <utility>
using namespace clang;
raw_ostream &RewriteBuffer::write(raw_ostream &os) const {
// 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;
}
/// Return true if this character is non-new-line whitespace:
/// ' ', '\\t', '\\f', '\\v', '\\r'.
static inline bool isWhitespaceExceptNL(unsigned char c) {
switch (c) {
case ' ':
case '\t':
case '\f':
case '\v':
case '\r':
return true;
default:
return false;
}
}
void RewriteBuffer::RemoveText(unsigned OrigOffset, unsigned Size,
bool removeLineIfEmpty) {
// 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);
if (removeLineIfEmpty) {
// Find the line that the remove occurred and if it is completely empty
// remove the line as well.
iterator curLineStart = begin();
unsigned curLineStartOffs = 0;
iterator posI = begin();
for (unsigned i = 0; i != RealOffset; ++i) {
if (*posI == '\n') {
curLineStart = posI;
++curLineStart;
curLineStartOffs = i + 1;
}
++posI;
}
unsigned lineSize = 0;
posI = curLineStart;
while (posI != end() && isWhitespaceExceptNL(*posI)) {
++posI;
++lineSize;
}
if (posI != end() && *posI == '\n') {
Buffer.erase(curLineStartOffs, lineSize + 1/* + '\n'*/);
AddReplaceDelta(curLineStartOffs, -(lineSize + 1/* + '\n'*/));
}
}
}
void RewriteBuffer::InsertText(unsigned OrigOffset, 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,
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,
RewriteOptions opts) const {
if (!isRewritable(Range.getBegin()) ||
!isRewritable(Range.getEnd())) return -1;
FileID StartFileID, EndFileID;
unsigned StartOff = getLocationOffsetAndFileID(Range.getBegin(), StartFileID);
unsigned 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, opts.IncludeInsertsAtEndOfRange);
StartOff = RB.getMappedOffset(StartOff, !opts.IncludeInsertsAtBeginOfRange);
}
// 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, RewriteOptions opts) const {
return getRangeSize(CharSourceRange::getTokenRange(Range), opts);
}
/// 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(CharSourceRange 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.
if (Range.isTokenRange())
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.
if (Range.isTokenRange())
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()));
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, StringRef Str,
bool InsertAfter, bool indentNewLines) {
if (!isRewritable(Loc)) return true;
FileID FID;
unsigned StartOffs = getLocationOffsetAndFileID(Loc, FID);
SmallString<128> indentedStr;
if (indentNewLines && Str.find('\n') != StringRef::npos) {
StringRef MB = SourceMgr->getBufferData(FID);
unsigned lineNo = SourceMgr->getLineNumber(FID, StartOffs) - 1;
const SrcMgr::ContentCache *
Content = SourceMgr->getSLocEntry(FID).getFile().getContentCache();
unsigned lineOffs = Content->SourceLineCache[lineNo];
// Find the whitespace at the start of the line.
StringRef indentSpace;
{
unsigned i = lineOffs;
while (isWhitespaceExceptNL(MB[i]))
++i;
indentSpace = MB.substr(lineOffs, i-lineOffs);
}
SmallVector<StringRef, 4> lines;
Str.split(lines, "\n");
for (unsigned i = 0, e = lines.size(); i != e; ++i) {
indentedStr += lines[i];
if (i < e-1) {
indentedStr += '\n';
indentedStr += indentSpace;
}
}
Str = indentedStr.str();
}
getEditBuffer(FID).InsertText(StartOffs, Str, InsertAfter);
return false;
}
bool Rewriter::InsertTextAfterToken(SourceLocation Loc, StringRef Str) {
if (!isRewritable(Loc)) return true;
FileID FID;
unsigned StartOffs = getLocationOffsetAndFileID(Loc, FID);
RewriteOptions rangeOpts;
rangeOpts.IncludeInsertsAtBeginOfRange = false;
StartOffs += getRangeSize(SourceRange(Loc, Loc), rangeOpts);
getEditBuffer(FID).InsertText(StartOffs, Str, /*InsertAfter*/true);
return false;
}
/// RemoveText - Remove the specified text region.
bool Rewriter::RemoveText(SourceLocation Start, unsigned Length,
RewriteOptions opts) {
if (!isRewritable(Start)) return true;
FileID FID;
unsigned StartOffs = getLocationOffsetAndFileID(Start, FID);
getEditBuffer(FID).RemoveText(StartOffs, Length, opts.RemoveLineIfEmpty);
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,
StringRef NewStr) {
if (!isRewritable(Start)) return true;
FileID StartFileID;
unsigned StartOffs = getLocationOffsetAndFileID(Start, StartFileID);
getEditBuffer(StartFileID).ReplaceText(StartOffs, OrigLength, NewStr);
return false;
}
bool Rewriter::ReplaceText(SourceRange range, SourceRange replacementRange) {
if (!isRewritable(range.getBegin())) return true;
if (!isRewritable(range.getEnd())) return true;
if (replacementRange.isInvalid()) return true;
SourceLocation start = range.getBegin();
unsigned origLength = getRangeSize(range);
unsigned newLength = getRangeSize(replacementRange);
FileID FID;
unsigned newOffs = getLocationOffsetAndFileID(replacementRange.getBegin(),
FID);
StringRef MB = SourceMgr->getBufferData(FID);
return ReplaceText(start, origLength, MB.substr(newOffs, newLength));
}
bool Rewriter::IncreaseIndentation(CharSourceRange range,
SourceLocation parentIndent) {
if (range.isInvalid()) return true;
if (!isRewritable(range.getBegin())) return true;
if (!isRewritable(range.getEnd())) return true;
if (!isRewritable(parentIndent)) return true;
FileID StartFileID, EndFileID, parentFileID;
unsigned StartOff, EndOff, parentOff;
StartOff = getLocationOffsetAndFileID(range.getBegin(), StartFileID);
EndOff = getLocationOffsetAndFileID(range.getEnd(), EndFileID);
parentOff = getLocationOffsetAndFileID(parentIndent, parentFileID);
if (StartFileID != EndFileID || StartFileID != parentFileID)
return true;
if (StartOff > EndOff)
return true;
FileID FID = StartFileID;
StringRef MB = SourceMgr->getBufferData(FID);
unsigned parentLineNo = SourceMgr->getLineNumber(FID, parentOff) - 1;
unsigned startLineNo = SourceMgr->getLineNumber(FID, StartOff) - 1;
unsigned endLineNo = SourceMgr->getLineNumber(FID, EndOff) - 1;
const SrcMgr::ContentCache *
Content = SourceMgr->getSLocEntry(FID).getFile().getContentCache();
// Find where the lines start.
unsigned parentLineOffs = Content->SourceLineCache[parentLineNo];
unsigned startLineOffs = Content->SourceLineCache[startLineNo];
// Find the whitespace at the start of each line.
StringRef parentSpace, startSpace;
{
unsigned i = parentLineOffs;
while (isWhitespaceExceptNL(MB[i]))
++i;
parentSpace = MB.substr(parentLineOffs, i-parentLineOffs);
i = startLineOffs;
while (isWhitespaceExceptNL(MB[i]))
++i;
startSpace = MB.substr(startLineOffs, i-startLineOffs);
}
if (parentSpace.size() >= startSpace.size())
return true;
if (!startSpace.startswith(parentSpace))
return true;
StringRef indent = startSpace.substr(parentSpace.size());
// Indent the lines between start/end offsets.
RewriteBuffer &RB = getEditBuffer(FID);
for (unsigned lineNo = startLineNo; lineNo <= endLineNo; ++lineNo) {
unsigned offs = Content->SourceLineCache[lineNo];
unsigned i = offs;
while (isWhitespaceExceptNL(MB[i]))
++i;
StringRef origIndent = MB.substr(offs, i-offs);
if (origIndent.startswith(startSpace))
RB.InsertText(offs, indent, /*InsertAfter=*/false);
}
return false;
}
namespace {
// A wrapper for a file stream that atomically overwrites the target.
//
// Creates a file output stream for a temporary file in the constructor,
// which is later accessible via getStream() if ok() return true.
// Flushes the stream and moves the temporary file to the target location
// in the destructor.
class AtomicallyMovedFile {
public:
AtomicallyMovedFile(DiagnosticsEngine &Diagnostics, StringRef Filename,
bool &AllWritten)
: Diagnostics(Diagnostics), Filename(Filename), AllWritten(AllWritten) {
TempFilename = Filename;
TempFilename += "-%%%%%%%%";
int FD;
if (llvm::sys::fs::createUniqueFile(TempFilename, FD, TempFilename)) {
AllWritten = false;
Diagnostics.Report(clang::diag::err_unable_to_make_temp)
<< TempFilename;
} else {
FileStream.reset(new llvm::raw_fd_ostream(FD, /*shouldClose=*/true));
}
}
~AtomicallyMovedFile() {
if (!ok()) return;
// Close (will also flush) theFileStream.
FileStream->close();
if (std::error_code ec = llvm::sys::fs::rename(TempFilename, Filename)) {
AllWritten = false;
Diagnostics.Report(clang::diag::err_unable_to_rename_temp)
<< TempFilename << Filename << ec.message();
// If the remove fails, there's not a lot we can do - this is already an
// error.
llvm::sys::fs::remove(TempFilename);
}
}
bool ok() { return (bool)FileStream; }
raw_ostream &getStream() { return *FileStream; }
private:
DiagnosticsEngine &Diagnostics;
StringRef Filename;
SmallString<128> TempFilename;
std::unique_ptr<llvm::raw_fd_ostream> FileStream;
bool &AllWritten;
};
} // namespace
bool Rewriter::overwriteChangedFiles() {
bool AllWritten = true;
for (buffer_iterator I = buffer_begin(), E = buffer_end(); I != E; ++I) {
const FileEntry *Entry =
getSourceMgr().getFileEntryForID(I->first);
AtomicallyMovedFile File(getSourceMgr().getDiagnostics(), Entry->getName(),
AllWritten);
if (File.ok()) {
I->second.write(File.getStream());
}
}
return !AllWritten;
}
