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/FileManager.h"
19 #include "clang/Basic/SourceLocation.h"
20 #include "clang/Basic/SourceManager.h"
21 #include "clang/Lex/Lexer.h"
22 #include "clang/Rewrite/Core/RewriteBuffer.h"
23 #include "clang/Rewrite/Core/RewriteRope.h"
24 #include "llvm/ADT/SmallString.h"
25 #include "llvm/ADT/SmallVector.h"
26 #include "llvm/ADT/StringRef.h"
27 #include "llvm/Support/FileSystem.h"
28 #include "llvm/Support/raw_ostream.h"
29 #include <cassert>
30 #include <iterator>
31 #include <map>
32 #include <memory>
33 #include <system_error>
34 #include <utility>
35
36 using namespace clang;
37
write(raw_ostream & os) const38 raw_ostream &RewriteBuffer::write(raw_ostream &os) const {
39 // Walk RewriteRope chunks efficiently using MoveToNextPiece() instead of the
40 // character iterator.
41 for (RopePieceBTreeIterator I = begin(), E = end(); I != E;
42 I.MoveToNextPiece())
43 os << I.piece();
44 return os;
45 }
46
47 /// Return true if this character is non-new-line whitespace:
48 /// ' ', '\\t', '\\f', '\\v', '\\r'.
isWhitespaceExceptNL(unsigned char c)49 static inline bool isWhitespaceExceptNL(unsigned char c) {
50 switch (c) {
51 case ' ':
52 case '\t':
53 case '\f':
54 case '\v':
55 case '\r':
56 return true;
57 default:
58 return false;
59 }
60 }
61
RemoveText(unsigned OrigOffset,unsigned Size,bool removeLineIfEmpty)62 void RewriteBuffer::RemoveText(unsigned OrigOffset, unsigned Size,
63 bool removeLineIfEmpty) {
64 // Nothing to remove, exit early.
65 if (Size == 0) return;
66
67 unsigned RealOffset = getMappedOffset(OrigOffset, true);
68 assert(RealOffset+Size <= Buffer.size() && "Invalid location");
69
70 // Remove the dead characters.
71 Buffer.erase(RealOffset, Size);
72
73 // Add a delta so that future changes are offset correctly.
74 AddReplaceDelta(OrigOffset, -Size);
75
76 if (removeLineIfEmpty) {
77 // Find the line that the remove occurred and if it is completely empty
78 // remove the line as well.
79
80 iterator curLineStart = begin();
81 unsigned curLineStartOffs = 0;
82 iterator posI = begin();
83 for (unsigned i = 0; i != RealOffset; ++i) {
84 if (*posI == '\n') {
85 curLineStart = posI;
86 ++curLineStart;
87 curLineStartOffs = i + 1;
88 }
89 ++posI;
90 }
91
92 unsigned lineSize = 0;
93 posI = curLineStart;
94 while (posI != end() && isWhitespaceExceptNL(*posI)) {
95 ++posI;
96 ++lineSize;
97 }
98 if (posI != end() && *posI == '\n') {
99 Buffer.erase(curLineStartOffs, lineSize + 1/* + '\n'*/);
100 AddReplaceDelta(curLineStartOffs, -(lineSize + 1/* + '\n'*/));
101 }
102 }
103 }
104
InsertText(unsigned OrigOffset,StringRef Str,bool InsertAfter)105 void RewriteBuffer::InsertText(unsigned OrigOffset, StringRef Str,
106 bool InsertAfter) {
107 // Nothing to insert, exit early.
108 if (Str.empty()) return;
109
110 unsigned RealOffset = getMappedOffset(OrigOffset, InsertAfter);
111 Buffer.insert(RealOffset, Str.begin(), Str.end());
112
113 // Add a delta so that future changes are offset correctly.
114 AddInsertDelta(OrigOffset, Str.size());
115 }
116
117 /// ReplaceText - This method replaces a range of characters in the input
118 /// buffer with a new string. This is effectively a combined "remove+insert"
119 /// operation.
ReplaceText(unsigned OrigOffset,unsigned OrigLength,StringRef NewStr)120 void RewriteBuffer::ReplaceText(unsigned OrigOffset, unsigned OrigLength,
121 StringRef NewStr) {
122 unsigned RealOffset = getMappedOffset(OrigOffset, true);
123 Buffer.erase(RealOffset, OrigLength);
124 Buffer.insert(RealOffset, NewStr.begin(), NewStr.end());
125 if (OrigLength != NewStr.size())
126 AddReplaceDelta(OrigOffset, NewStr.size() - OrigLength);
127 }
128
129 //===----------------------------------------------------------------------===//
130 // Rewriter class
131 //===----------------------------------------------------------------------===//
132
133 /// getRangeSize - Return the size in bytes of the specified range if they
134 /// are in the same file. If not, this returns -1.
getRangeSize(const CharSourceRange & Range,RewriteOptions opts) const135 int Rewriter::getRangeSize(const CharSourceRange &Range,
136 RewriteOptions opts) const {
137 if (!isRewritable(Range.getBegin()) ||
138 !isRewritable(Range.getEnd())) return -1;
139
140 FileID StartFileID, EndFileID;
141 unsigned StartOff = getLocationOffsetAndFileID(Range.getBegin(), StartFileID);
142 unsigned EndOff = getLocationOffsetAndFileID(Range.getEnd(), EndFileID);
143
144 if (StartFileID != EndFileID)
145 return -1;
146
147 // If edits have been made to this buffer, the delta between the range may
148 // have changed.
149 std::map<FileID, RewriteBuffer>::const_iterator I =
150 RewriteBuffers.find(StartFileID);
151 if (I != RewriteBuffers.end()) {
152 const RewriteBuffer &RB = I->second;
153 EndOff = RB.getMappedOffset(EndOff, opts.IncludeInsertsAtEndOfRange);
154 StartOff = RB.getMappedOffset(StartOff, !opts.IncludeInsertsAtBeginOfRange);
155 }
156
157 // Adjust the end offset to the end of the last token, instead of being the
158 // start of the last token if this is a token range.
159 if (Range.isTokenRange())
160 EndOff += Lexer::MeasureTokenLength(Range.getEnd(), *SourceMgr, *LangOpts);
161
162 return EndOff-StartOff;
163 }
164
getRangeSize(SourceRange Range,RewriteOptions opts) const165 int Rewriter::getRangeSize(SourceRange Range, RewriteOptions opts) const {
166 return getRangeSize(CharSourceRange::getTokenRange(Range), opts);
167 }
168
169 /// getRewrittenText - Return the rewritten form of the text in the specified
170 /// range. If the start or end of the range was unrewritable or if they are
171 /// in different buffers, this returns an empty string.
172 ///
173 /// Note that this method is not particularly efficient.
getRewrittenText(SourceRange Range) const174 std::string Rewriter::getRewrittenText(SourceRange Range) const {
175 if (!isRewritable(Range.getBegin()) ||
176 !isRewritable(Range.getEnd()))
177 return {};
178
179 FileID StartFileID, EndFileID;
180 unsigned StartOff, EndOff;
181 StartOff = getLocationOffsetAndFileID(Range.getBegin(), StartFileID);
182 EndOff = getLocationOffsetAndFileID(Range.getEnd(), EndFileID);
183
184 if (StartFileID != EndFileID)
185 return {}; // Start and end in different buffers.
186
187 // If edits have been made to this buffer, the delta between the range may
188 // have changed.
189 std::map<FileID, RewriteBuffer>::const_iterator I =
190 RewriteBuffers.find(StartFileID);
191 if (I == RewriteBuffers.end()) {
192 // If the buffer hasn't been rewritten, just return the text from the input.
193 const char *Ptr = SourceMgr->getCharacterData(Range.getBegin());
194
195 // Adjust the end offset to the end of the last token, instead of being the
196 // start of the last token.
197 EndOff += Lexer::MeasureTokenLength(Range.getEnd(), *SourceMgr, *LangOpts);
198 return std::string(Ptr, Ptr+EndOff-StartOff);
199 }
200
201 const RewriteBuffer &RB = I->second;
202 EndOff = RB.getMappedOffset(EndOff, true);
203 StartOff = RB.getMappedOffset(StartOff);
204
205 // Adjust the end offset to the end of the last token, instead of being the
206 // start of the last token.
207 EndOff += Lexer::MeasureTokenLength(Range.getEnd(), *SourceMgr, *LangOpts);
208
209 // Advance the iterators to the right spot, yay for linear time algorithms.
210 RewriteBuffer::iterator Start = RB.begin();
211 std::advance(Start, StartOff);
212 RewriteBuffer::iterator End = Start;
213 std::advance(End, EndOff-StartOff);
214
215 return std::string(Start, End);
216 }
217
getLocationOffsetAndFileID(SourceLocation Loc,FileID & FID) const218 unsigned Rewriter::getLocationOffsetAndFileID(SourceLocation Loc,
219 FileID &FID) const {
220 assert(Loc.isValid() && "Invalid location");
221 std::pair<FileID, unsigned> V = SourceMgr->getDecomposedLoc(Loc);
222 FID = V.first;
223 return V.second;
224 }
225
226 /// getEditBuffer - Get or create a RewriteBuffer for the specified FileID.
getEditBuffer(FileID FID)227 RewriteBuffer &Rewriter::getEditBuffer(FileID FID) {
228 std::map<FileID, RewriteBuffer>::iterator I =
229 RewriteBuffers.lower_bound(FID);
230 if (I != RewriteBuffers.end() && I->first == FID)
231 return I->second;
232 I = RewriteBuffers.insert(I, std::make_pair(FID, RewriteBuffer()));
233
234 StringRef MB = SourceMgr->getBufferData(FID);
235 I->second.Initialize(MB.begin(), MB.end());
236
237 return I->second;
238 }
239
240 /// InsertText - Insert the specified string at the specified location in the
241 /// original buffer.
InsertText(SourceLocation Loc,StringRef Str,bool InsertAfter,bool indentNewLines)242 bool Rewriter::InsertText(SourceLocation Loc, StringRef Str,
243 bool InsertAfter, bool indentNewLines) {
244 if (!isRewritable(Loc)) return true;
245 FileID FID;
246 unsigned StartOffs = getLocationOffsetAndFileID(Loc, FID);
247
248 SmallString<128> indentedStr;
249 if (indentNewLines && Str.find('\n') != StringRef::npos) {
250 StringRef MB = SourceMgr->getBufferData(FID);
251
252 unsigned lineNo = SourceMgr->getLineNumber(FID, StartOffs) - 1;
253 const SrcMgr::ContentCache *
254 Content = SourceMgr->getSLocEntry(FID).getFile().getContentCache();
255 unsigned lineOffs = Content->SourceLineCache[lineNo];
256
257 // Find the whitespace at the start of the line.
258 StringRef indentSpace;
259 {
260 unsigned i = lineOffs;
261 while (isWhitespaceExceptNL(MB[i]))
262 ++i;
263 indentSpace = MB.substr(lineOffs, i-lineOffs);
264 }
265
266 SmallVector<StringRef, 4> lines;
267 Str.split(lines, "\n");
268
269 for (unsigned i = 0, e = lines.size(); i != e; ++i) {
270 indentedStr += lines[i];
271 if (i < e-1) {
272 indentedStr += '\n';
273 indentedStr += indentSpace;
274 }
275 }
276 Str = indentedStr.str();
277 }
278
279 getEditBuffer(FID).InsertText(StartOffs, Str, InsertAfter);
280 return false;
281 }
282
InsertTextAfterToken(SourceLocation Loc,StringRef Str)283 bool Rewriter::InsertTextAfterToken(SourceLocation Loc, StringRef Str) {
284 if (!isRewritable(Loc)) return true;
285 FileID FID;
286 unsigned StartOffs = getLocationOffsetAndFileID(Loc, FID);
287 RewriteOptions rangeOpts;
288 rangeOpts.IncludeInsertsAtBeginOfRange = false;
289 StartOffs += getRangeSize(SourceRange(Loc, Loc), rangeOpts);
290 getEditBuffer(FID).InsertText(StartOffs, Str, /*InsertAfter*/true);
291 return false;
292 }
293
294 /// RemoveText - Remove the specified text region.
RemoveText(SourceLocation Start,unsigned Length,RewriteOptions opts)295 bool Rewriter::RemoveText(SourceLocation Start, unsigned Length,
296 RewriteOptions opts) {
297 if (!isRewritable(Start)) return true;
298 FileID FID;
299 unsigned StartOffs = getLocationOffsetAndFileID(Start, FID);
300 getEditBuffer(FID).RemoveText(StartOffs, Length, opts.RemoveLineIfEmpty);
301 return false;
302 }
303
304 /// ReplaceText - This method replaces a range of characters in the input
305 /// buffer with a new string. This is effectively a combined "remove/insert"
306 /// operation.
ReplaceText(SourceLocation Start,unsigned OrigLength,StringRef NewStr)307 bool Rewriter::ReplaceText(SourceLocation Start, unsigned OrigLength,
308 StringRef NewStr) {
309 if (!isRewritable(Start)) return true;
310 FileID StartFileID;
311 unsigned StartOffs = getLocationOffsetAndFileID(Start, StartFileID);
312
313 getEditBuffer(StartFileID).ReplaceText(StartOffs, OrigLength, NewStr);
314 return false;
315 }
316
ReplaceText(SourceRange range,SourceRange replacementRange)317 bool Rewriter::ReplaceText(SourceRange range, SourceRange replacementRange) {
318 if (!isRewritable(range.getBegin())) return true;
319 if (!isRewritable(range.getEnd())) return true;
320 if (replacementRange.isInvalid()) return true;
321 SourceLocation start = range.getBegin();
322 unsigned origLength = getRangeSize(range);
323 unsigned newLength = getRangeSize(replacementRange);
324 FileID FID;
325 unsigned newOffs = getLocationOffsetAndFileID(replacementRange.getBegin(),
326 FID);
327 StringRef MB = SourceMgr->getBufferData(FID);
328 return ReplaceText(start, origLength, MB.substr(newOffs, newLength));
329 }
330
IncreaseIndentation(CharSourceRange range,SourceLocation parentIndent)331 bool Rewriter::IncreaseIndentation(CharSourceRange range,
332 SourceLocation parentIndent) {
333 if (range.isInvalid()) return true;
334 if (!isRewritable(range.getBegin())) return true;
335 if (!isRewritable(range.getEnd())) return true;
336 if (!isRewritable(parentIndent)) return true;
337
338 FileID StartFileID, EndFileID, parentFileID;
339 unsigned StartOff, EndOff, parentOff;
340
341 StartOff = getLocationOffsetAndFileID(range.getBegin(), StartFileID);
342 EndOff = getLocationOffsetAndFileID(range.getEnd(), EndFileID);
343 parentOff = getLocationOffsetAndFileID(parentIndent, parentFileID);
344
345 if (StartFileID != EndFileID || StartFileID != parentFileID)
346 return true;
347 if (StartOff > EndOff)
348 return true;
349
350 FileID FID = StartFileID;
351 StringRef MB = SourceMgr->getBufferData(FID);
352
353 unsigned parentLineNo = SourceMgr->getLineNumber(FID, parentOff) - 1;
354 unsigned startLineNo = SourceMgr->getLineNumber(FID, StartOff) - 1;
355 unsigned endLineNo = SourceMgr->getLineNumber(FID, EndOff) - 1;
356
357 const SrcMgr::ContentCache *
358 Content = SourceMgr->getSLocEntry(FID).getFile().getContentCache();
359
360 // Find where the lines start.
361 unsigned parentLineOffs = Content->SourceLineCache[parentLineNo];
362 unsigned startLineOffs = Content->SourceLineCache[startLineNo];
363
364 // Find the whitespace at the start of each line.
365 StringRef parentSpace, startSpace;
366 {
367 unsigned i = parentLineOffs;
368 while (isWhitespaceExceptNL(MB[i]))
369 ++i;
370 parentSpace = MB.substr(parentLineOffs, i-parentLineOffs);
371
372 i = startLineOffs;
373 while (isWhitespaceExceptNL(MB[i]))
374 ++i;
375 startSpace = MB.substr(startLineOffs, i-startLineOffs);
376 }
377 if (parentSpace.size() >= startSpace.size())
378 return true;
379 if (!startSpace.startswith(parentSpace))
380 return true;
381
382 StringRef indent = startSpace.substr(parentSpace.size());
383
384 // Indent the lines between start/end offsets.
385 RewriteBuffer &RB = getEditBuffer(FID);
386 for (unsigned lineNo = startLineNo; lineNo <= endLineNo; ++lineNo) {
387 unsigned offs = Content->SourceLineCache[lineNo];
388 unsigned i = offs;
389 while (isWhitespaceExceptNL(MB[i]))
390 ++i;
391 StringRef origIndent = MB.substr(offs, i-offs);
392 if (origIndent.startswith(startSpace))
393 RB.InsertText(offs, indent, /*InsertAfter=*/false);
394 }
395
396 return false;
397 }
398
399 namespace {
400
401 // A wrapper for a file stream that atomically overwrites the target.
402 //
403 // Creates a file output stream for a temporary file in the constructor,
404 // which is later accessible via getStream() if ok() return true.
405 // Flushes the stream and moves the temporary file to the target location
406 // in the destructor.
407 class AtomicallyMovedFile {
408 public:
AtomicallyMovedFile(DiagnosticsEngine & Diagnostics,StringRef Filename,bool & AllWritten)409 AtomicallyMovedFile(DiagnosticsEngine &Diagnostics, StringRef Filename,
410 bool &AllWritten)
411 : Diagnostics(Diagnostics), Filename(Filename), AllWritten(AllWritten) {
412 TempFilename = Filename;
413 TempFilename += "-%%%%%%%%";
414 int FD;
415 if (llvm::sys::fs::createUniqueFile(TempFilename, FD, TempFilename)) {
416 AllWritten = false;
417 Diagnostics.Report(clang::diag::err_unable_to_make_temp)
418 << TempFilename;
419 } else {
420 FileStream.reset(new llvm::raw_fd_ostream(FD, /*shouldClose=*/true));
421 }
422 }
423
~AtomicallyMovedFile()424 ~AtomicallyMovedFile() {
425 if (!ok()) return;
426
427 // Close (will also flush) theFileStream.
428 FileStream->close();
429 if (std::error_code ec = llvm::sys::fs::rename(TempFilename, Filename)) {
430 AllWritten = false;
431 Diagnostics.Report(clang::diag::err_unable_to_rename_temp)
432 << TempFilename << Filename << ec.message();
433 // If the remove fails, there's not a lot we can do - this is already an
434 // error.
435 llvm::sys::fs::remove(TempFilename);
436 }
437 }
438
ok()439 bool ok() { return (bool)FileStream; }
getStream()440 raw_ostream &getStream() { return *FileStream; }
441
442 private:
443 DiagnosticsEngine &Diagnostics;
444 StringRef Filename;
445 SmallString<128> TempFilename;
446 std::unique_ptr<llvm::raw_fd_ostream> FileStream;
447 bool &AllWritten;
448 };
449
450 } // namespace
451
overwriteChangedFiles()452 bool Rewriter::overwriteChangedFiles() {
453 bool AllWritten = true;
454 for (buffer_iterator I = buffer_begin(), E = buffer_end(); I != E; ++I) {
455 const FileEntry *Entry =
456 getSourceMgr().getFileEntryForID(I->first);
457 AtomicallyMovedFile File(getSourceMgr().getDiagnostics(), Entry->getName(),
458 AllWritten);
459 if (File.ok()) {
460 I->second.write(File.getStream());
461 }
462 }
463 return !AllWritten;
464 }
465