1 //===--- Rewriter.cpp - Code rewriting interface --------------------------===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file defines the Rewriter class, which is used for code
11 // transformations.
12 //
13 //===----------------------------------------------------------------------===//
14
15 #include "clang/Rewrite/Core/Rewriter.h"
16 #include "clang/Basic/Diagnostic.h"
17 #include "clang/Basic/DiagnosticIDs.h"
18 #include "clang/Basic/SourceManager.h"
19 #include "clang/Lex/Lexer.h"
20 #include "llvm/ADT/SmallString.h"
21 #include "llvm/Support/FileSystem.h"
22 #include "llvm/Support/raw_ostream.h"
23 using namespace clang;
24
write(raw_ostream & os) const25 raw_ostream &RewriteBuffer::write(raw_ostream &os) const {
26 // Walk RewriteRope chunks efficiently using MoveToNextPiece() instead of the
27 // character iterator.
28 for (RopePieceBTreeIterator I = begin(), E = end(); I != E;
29 I.MoveToNextPiece())
30 os << I.piece();
31 return os;
32 }
33
34 /// \brief Return true if this character is non-new-line whitespace:
35 /// ' ', '\\t', '\\f', '\\v', '\\r'.
isWhitespaceExceptNL(unsigned char c)36 static inline bool isWhitespaceExceptNL(unsigned char c) {
37 switch (c) {
38 case ' ':
39 case '\t':
40 case '\f':
41 case '\v':
42 case '\r':
43 return true;
44 default:
45 return false;
46 }
47 }
48
RemoveText(unsigned OrigOffset,unsigned Size,bool removeLineIfEmpty)49 void RewriteBuffer::RemoveText(unsigned OrigOffset, unsigned Size,
50 bool removeLineIfEmpty) {
51 // Nothing to remove, exit early.
52 if (Size == 0) return;
53
54 unsigned RealOffset = getMappedOffset(OrigOffset, true);
55 assert(RealOffset+Size <= Buffer.size() && "Invalid location");
56
57 // Remove the dead characters.
58 Buffer.erase(RealOffset, Size);
59
60 // Add a delta so that future changes are offset correctly.
61 AddReplaceDelta(OrigOffset, -Size);
62
63 if (removeLineIfEmpty) {
64 // Find the line that the remove occurred and if it is completely empty
65 // remove the line as well.
66
67 iterator curLineStart = begin();
68 unsigned curLineStartOffs = 0;
69 iterator posI = begin();
70 for (unsigned i = 0; i != RealOffset; ++i) {
71 if (*posI == '\n') {
72 curLineStart = posI;
73 ++curLineStart;
74 curLineStartOffs = i + 1;
75 }
76 ++posI;
77 }
78
79 unsigned lineSize = 0;
80 posI = curLineStart;
81 while (posI != end() && isWhitespaceExceptNL(*posI)) {
82 ++posI;
83 ++lineSize;
84 }
85 if (posI != end() && *posI == '\n') {
86 Buffer.erase(curLineStartOffs, lineSize + 1/* + '\n'*/);
87 AddReplaceDelta(curLineStartOffs, -(lineSize + 1/* + '\n'*/));
88 }
89 }
90 }
91
InsertText(unsigned OrigOffset,StringRef Str,bool InsertAfter)92 void RewriteBuffer::InsertText(unsigned OrigOffset, StringRef Str,
93 bool InsertAfter) {
94
95 // Nothing to insert, exit early.
96 if (Str.empty()) return;
97
98 unsigned RealOffset = getMappedOffset(OrigOffset, InsertAfter);
99 Buffer.insert(RealOffset, Str.begin(), Str.end());
100
101 // Add a delta so that future changes are offset correctly.
102 AddInsertDelta(OrigOffset, Str.size());
103 }
104
105 /// ReplaceText - This method replaces a range of characters in the input
106 /// buffer with a new string. This is effectively a combined "remove+insert"
107 /// operation.
ReplaceText(unsigned OrigOffset,unsigned OrigLength,StringRef NewStr)108 void RewriteBuffer::ReplaceText(unsigned OrigOffset, unsigned OrigLength,
109 StringRef NewStr) {
110 unsigned RealOffset = getMappedOffset(OrigOffset, true);
111 Buffer.erase(RealOffset, OrigLength);
112 Buffer.insert(RealOffset, NewStr.begin(), NewStr.end());
113 if (OrigLength != NewStr.size())
114 AddReplaceDelta(OrigOffset, NewStr.size() - OrigLength);
115 }
116
117
118 //===----------------------------------------------------------------------===//
119 // Rewriter class
120 //===----------------------------------------------------------------------===//
121
122 /// getRangeSize - Return the size in bytes of the specified range if they
123 /// are in the same file. If not, this returns -1.
getRangeSize(const CharSourceRange & Range,RewriteOptions opts) const124 int Rewriter::getRangeSize(const CharSourceRange &Range,
125 RewriteOptions opts) const {
126 if (!isRewritable(Range.getBegin()) ||
127 !isRewritable(Range.getEnd())) return -1;
128
129 FileID StartFileID, EndFileID;
130 unsigned StartOff, EndOff;
131
132 StartOff = getLocationOffsetAndFileID(Range.getBegin(), StartFileID);
133 EndOff = getLocationOffsetAndFileID(Range.getEnd(), EndFileID);
134
135 if (StartFileID != EndFileID)
136 return -1;
137
138 // If edits have been made to this buffer, the delta between the range may
139 // have changed.
140 std::map<FileID, RewriteBuffer>::const_iterator I =
141 RewriteBuffers.find(StartFileID);
142 if (I != RewriteBuffers.end()) {
143 const RewriteBuffer &RB = I->second;
144 EndOff = RB.getMappedOffset(EndOff, opts.IncludeInsertsAtEndOfRange);
145 StartOff = RB.getMappedOffset(StartOff, !opts.IncludeInsertsAtBeginOfRange);
146 }
147
148
149 // Adjust the end offset to the end of the last token, instead of being the
150 // start of the last token if this is a token range.
151 if (Range.isTokenRange())
152 EndOff += Lexer::MeasureTokenLength(Range.getEnd(), *SourceMgr, *LangOpts);
153
154 return EndOff-StartOff;
155 }
156
getRangeSize(SourceRange Range,RewriteOptions opts) const157 int Rewriter::getRangeSize(SourceRange Range, RewriteOptions opts) const {
158 return getRangeSize(CharSourceRange::getTokenRange(Range), opts);
159 }
160
161
162 /// getRewrittenText - Return the rewritten form of the text in the specified
163 /// range. If the start or end of the range was unrewritable or if they are
164 /// in different buffers, this returns an empty string.
165 ///
166 /// Note that this method is not particularly efficient.
167 ///
getRewrittenText(SourceRange Range) const168 std::string Rewriter::getRewrittenText(SourceRange Range) const {
169 if (!isRewritable(Range.getBegin()) ||
170 !isRewritable(Range.getEnd()))
171 return "";
172
173 FileID StartFileID, EndFileID;
174 unsigned StartOff, EndOff;
175 StartOff = getLocationOffsetAndFileID(Range.getBegin(), StartFileID);
176 EndOff = getLocationOffsetAndFileID(Range.getEnd(), EndFileID);
177
178 if (StartFileID != EndFileID)
179 return ""; // Start and end in different buffers.
180
181 // If edits have been made to this buffer, the delta between the range may
182 // have changed.
183 std::map<FileID, RewriteBuffer>::const_iterator I =
184 RewriteBuffers.find(StartFileID);
185 if (I == RewriteBuffers.end()) {
186 // If the buffer hasn't been rewritten, just return the text from the input.
187 const char *Ptr = SourceMgr->getCharacterData(Range.getBegin());
188
189 // Adjust the end offset to the end of the last token, instead of being the
190 // start of the last token.
191 EndOff += Lexer::MeasureTokenLength(Range.getEnd(), *SourceMgr, *LangOpts);
192 return std::string(Ptr, Ptr+EndOff-StartOff);
193 }
194
195 const RewriteBuffer &RB = I->second;
196 EndOff = RB.getMappedOffset(EndOff, true);
197 StartOff = RB.getMappedOffset(StartOff);
198
199 // Adjust the end offset to the end of the last token, instead of being the
200 // start of the last token.
201 EndOff += Lexer::MeasureTokenLength(Range.getEnd(), *SourceMgr, *LangOpts);
202
203 // Advance the iterators to the right spot, yay for linear time algorithms.
204 RewriteBuffer::iterator Start = RB.begin();
205 std::advance(Start, StartOff);
206 RewriteBuffer::iterator End = Start;
207 std::advance(End, EndOff-StartOff);
208
209 return std::string(Start, End);
210 }
211
getLocationOffsetAndFileID(SourceLocation Loc,FileID & FID) const212 unsigned Rewriter::getLocationOffsetAndFileID(SourceLocation Loc,
213 FileID &FID) const {
214 assert(Loc.isValid() && "Invalid location");
215 std::pair<FileID,unsigned> V = SourceMgr->getDecomposedLoc(Loc);
216 FID = V.first;
217 return V.second;
218 }
219
220
221 /// getEditBuffer - Get or create a RewriteBuffer for the specified FileID.
222 ///
getEditBuffer(FileID FID)223 RewriteBuffer &Rewriter::getEditBuffer(FileID FID) {
224 std::map<FileID, RewriteBuffer>::iterator I =
225 RewriteBuffers.lower_bound(FID);
226 if (I != RewriteBuffers.end() && I->first == FID)
227 return I->second;
228 I = RewriteBuffers.insert(I, std::make_pair(FID, RewriteBuffer()));
229
230 StringRef MB = SourceMgr->getBufferData(FID);
231 I->second.Initialize(MB.begin(), MB.end());
232
233 return I->second;
234 }
235
236 /// InsertText - Insert the specified string at the specified location in the
237 /// original buffer.
InsertText(SourceLocation Loc,StringRef Str,bool InsertAfter,bool indentNewLines)238 bool Rewriter::InsertText(SourceLocation Loc, StringRef Str,
239 bool InsertAfter, bool indentNewLines) {
240 if (!isRewritable(Loc)) return true;
241 FileID FID;
242 unsigned StartOffs = getLocationOffsetAndFileID(Loc, FID);
243
244 SmallString<128> indentedStr;
245 if (indentNewLines && Str.find('\n') != StringRef::npos) {
246 StringRef MB = SourceMgr->getBufferData(FID);
247
248 unsigned lineNo = SourceMgr->getLineNumber(FID, StartOffs) - 1;
249 const SrcMgr::ContentCache *
250 Content = SourceMgr->getSLocEntry(FID).getFile().getContentCache();
251 unsigned lineOffs = Content->SourceLineCache[lineNo];
252
253 // Find the whitespace at the start of the line.
254 StringRef indentSpace;
255 {
256 unsigned i = lineOffs;
257 while (isWhitespaceExceptNL(MB[i]))
258 ++i;
259 indentSpace = MB.substr(lineOffs, i-lineOffs);
260 }
261
262 SmallVector<StringRef, 4> lines;
263 Str.split(lines, "\n");
264
265 for (unsigned i = 0, e = lines.size(); i != e; ++i) {
266 indentedStr += lines[i];
267 if (i < e-1) {
268 indentedStr += '\n';
269 indentedStr += indentSpace;
270 }
271 }
272 Str = indentedStr.str();
273 }
274
275 getEditBuffer(FID).InsertText(StartOffs, Str, InsertAfter);
276 return false;
277 }
278
InsertTextAfterToken(SourceLocation Loc,StringRef Str)279 bool Rewriter::InsertTextAfterToken(SourceLocation Loc, StringRef Str) {
280 if (!isRewritable(Loc)) return true;
281 FileID FID;
282 unsigned StartOffs = getLocationOffsetAndFileID(Loc, FID);
283 RewriteOptions rangeOpts;
284 rangeOpts.IncludeInsertsAtBeginOfRange = false;
285 StartOffs += getRangeSize(SourceRange(Loc, Loc), rangeOpts);
286 getEditBuffer(FID).InsertText(StartOffs, Str, /*InsertAfter*/true);
287 return false;
288 }
289
290 /// RemoveText - Remove the specified text region.
RemoveText(SourceLocation Start,unsigned Length,RewriteOptions opts)291 bool Rewriter::RemoveText(SourceLocation Start, unsigned Length,
292 RewriteOptions opts) {
293 if (!isRewritable(Start)) return true;
294 FileID FID;
295 unsigned StartOffs = getLocationOffsetAndFileID(Start, FID);
296 getEditBuffer(FID).RemoveText(StartOffs, Length, opts.RemoveLineIfEmpty);
297 return false;
298 }
299
300 /// ReplaceText - This method replaces a range of characters in the input
301 /// buffer with a new string. This is effectively a combined "remove/insert"
302 /// operation.
ReplaceText(SourceLocation Start,unsigned OrigLength,StringRef NewStr)303 bool Rewriter::ReplaceText(SourceLocation Start, unsigned OrigLength,
304 StringRef NewStr) {
305 if (!isRewritable(Start)) return true;
306 FileID StartFileID;
307 unsigned StartOffs = getLocationOffsetAndFileID(Start, StartFileID);
308
309 getEditBuffer(StartFileID).ReplaceText(StartOffs, OrigLength, NewStr);
310 return false;
311 }
312
ReplaceText(SourceRange range,SourceRange replacementRange)313 bool Rewriter::ReplaceText(SourceRange range, SourceRange replacementRange) {
314 if (!isRewritable(range.getBegin())) return true;
315 if (!isRewritable(range.getEnd())) return true;
316 if (replacementRange.isInvalid()) return true;
317 SourceLocation start = range.getBegin();
318 unsigned origLength = getRangeSize(range);
319 unsigned newLength = getRangeSize(replacementRange);
320 FileID FID;
321 unsigned newOffs = getLocationOffsetAndFileID(replacementRange.getBegin(),
322 FID);
323 StringRef MB = SourceMgr->getBufferData(FID);
324 return ReplaceText(start, origLength, MB.substr(newOffs, newLength));
325 }
326
IncreaseIndentation(CharSourceRange range,SourceLocation parentIndent)327 bool Rewriter::IncreaseIndentation(CharSourceRange range,
328 SourceLocation parentIndent) {
329 if (range.isInvalid()) return true;
330 if (!isRewritable(range.getBegin())) return true;
331 if (!isRewritable(range.getEnd())) return true;
332 if (!isRewritable(parentIndent)) return true;
333
334 FileID StartFileID, EndFileID, parentFileID;
335 unsigned StartOff, EndOff, parentOff;
336
337 StartOff = getLocationOffsetAndFileID(range.getBegin(), StartFileID);
338 EndOff = getLocationOffsetAndFileID(range.getEnd(), EndFileID);
339 parentOff = getLocationOffsetAndFileID(parentIndent, parentFileID);
340
341 if (StartFileID != EndFileID || StartFileID != parentFileID)
342 return true;
343 if (StartOff > EndOff)
344 return true;
345
346 FileID FID = StartFileID;
347 StringRef MB = SourceMgr->getBufferData(FID);
348
349 unsigned parentLineNo = SourceMgr->getLineNumber(FID, parentOff) - 1;
350 unsigned startLineNo = SourceMgr->getLineNumber(FID, StartOff) - 1;
351 unsigned endLineNo = SourceMgr->getLineNumber(FID, EndOff) - 1;
352
353 const SrcMgr::ContentCache *
354 Content = SourceMgr->getSLocEntry(FID).getFile().getContentCache();
355
356 // Find where the lines start.
357 unsigned parentLineOffs = Content->SourceLineCache[parentLineNo];
358 unsigned startLineOffs = Content->SourceLineCache[startLineNo];
359
360 // Find the whitespace at the start of each line.
361 StringRef parentSpace, startSpace;
362 {
363 unsigned i = parentLineOffs;
364 while (isWhitespaceExceptNL(MB[i]))
365 ++i;
366 parentSpace = MB.substr(parentLineOffs, i-parentLineOffs);
367
368 i = startLineOffs;
369 while (isWhitespaceExceptNL(MB[i]))
370 ++i;
371 startSpace = MB.substr(startLineOffs, i-startLineOffs);
372 }
373 if (parentSpace.size() >= startSpace.size())
374 return true;
375 if (!startSpace.startswith(parentSpace))
376 return true;
377
378 StringRef indent = startSpace.substr(parentSpace.size());
379
380 // Indent the lines between start/end offsets.
381 RewriteBuffer &RB = getEditBuffer(FID);
382 for (unsigned lineNo = startLineNo; lineNo <= endLineNo; ++lineNo) {
383 unsigned offs = Content->SourceLineCache[lineNo];
384 unsigned i = offs;
385 while (isWhitespaceExceptNL(MB[i]))
386 ++i;
387 StringRef origIndent = MB.substr(offs, i-offs);
388 if (origIndent.startswith(startSpace))
389 RB.InsertText(offs, indent, /*InsertAfter=*/false);
390 }
391
392 return false;
393 }
394
395 namespace {
396 // A wrapper for a file stream that atomically overwrites the target.
397 //
398 // Creates a file output stream for a temporary file in the constructor,
399 // which is later accessible via getStream() if ok() return true.
400 // Flushes the stream and moves the temporary file to the target location
401 // in the destructor.
402 class AtomicallyMovedFile {
403 public:
AtomicallyMovedFile(DiagnosticsEngine & Diagnostics,StringRef Filename,bool & AllWritten)404 AtomicallyMovedFile(DiagnosticsEngine &Diagnostics, StringRef Filename,
405 bool &AllWritten)
406 : Diagnostics(Diagnostics), Filename(Filename), AllWritten(AllWritten) {
407 TempFilename = Filename;
408 TempFilename += "-%%%%%%%%";
409 int FD;
410 if (llvm::sys::fs::createUniqueFile(TempFilename, FD, TempFilename)) {
411 AllWritten = false;
412 Diagnostics.Report(clang::diag::err_unable_to_make_temp)
413 << TempFilename;
414 } else {
415 FileStream.reset(new llvm::raw_fd_ostream(FD, /*shouldClose=*/true));
416 }
417 }
418
~AtomicallyMovedFile()419 ~AtomicallyMovedFile() {
420 if (!ok()) return;
421
422 // Close (will also flush) theFileStream.
423 FileStream->close();
424 if (std::error_code ec = llvm::sys::fs::rename(TempFilename, Filename)) {
425 AllWritten = false;
426 Diagnostics.Report(clang::diag::err_unable_to_rename_temp)
427 << TempFilename << Filename << ec.message();
428 // If the remove fails, there's not a lot we can do - this is already an
429 // error.
430 llvm::sys::fs::remove(TempFilename);
431 }
432 }
433
ok()434 bool ok() { return (bool)FileStream; }
getStream()435 raw_ostream &getStream() { return *FileStream; }
436
437 private:
438 DiagnosticsEngine &Diagnostics;
439 StringRef Filename;
440 SmallString<128> TempFilename;
441 std::unique_ptr<llvm::raw_fd_ostream> FileStream;
442 bool &AllWritten;
443 };
444 } // end anonymous namespace
445
overwriteChangedFiles()446 bool Rewriter::overwriteChangedFiles() {
447 bool AllWritten = true;
448 for (buffer_iterator I = buffer_begin(), E = buffer_end(); I != E; ++I) {
449 const FileEntry *Entry =
450 getSourceMgr().getFileEntryForID(I->first);
451 AtomicallyMovedFile File(getSourceMgr().getDiagnostics(), Entry->getName(),
452 AllWritten);
453 if (File.ok()) {
454 I->second.write(File.getStream());
455 }
456 }
457 return !AllWritten;
458 }
459