external/bsd/llvm/dist/clang/lib/Rewrite/Rewriter.cpp

   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/SourceManager.h"
  20 #include "clang/Lex/Lexer.h"
  21 #include "llvm/ADT/SmallString.h"
  22 #include "llvm/Config/llvm-config.h"
  23 #include "llvm/Support/FileSystem.h"
  24 #include "llvm/Support/raw_ostream.h"
  25 using namespace clang;
  26
  27 raw_ostream &RewriteBuffer::write(raw_ostream &os) const {
  28   // Walk RewriteRope chunks efficiently using MoveToNextPiece() instead of the
  29   // character iterator.
  30   for (RopePieceBTreeIterator I = begin(), E = end(); I != E;
  31        I.MoveToNextPiece())
  32     os << I.piece();
  33   return os;
  34 }
  35
  36 /// \brief Return true if this character is non-new-line whitespace:
  37 /// ' ', '\\t', '\\f', '\\v', '\\r'.
  38 static inline bool isWhitespace(unsigned char c) {
  39   switch (c) {
  40   case ' ':
  41   case '\t':
  42   case '\f':
  43   case '\v':
  44   case '\r':
  45     return true;
  46   default:
  47     return false;
  48   }
  49 }
  50
  51 void RewriteBuffer::RemoveText(unsigned OrigOffset, unsigned Size,
  52                                bool removeLineIfEmpty) {
  53   // Nothing to remove, exit early.
  54   if (Size == 0) return;
  55
  56   unsigned RealOffset = getMappedOffset(OrigOffset, true);
  57   assert(RealOffset+Size < Buffer.size() && "Invalid location");
  58
  59   // Remove the dead characters.
  60   Buffer.erase(RealOffset, Size);
  61
  62   // Add a delta so that future changes are offset correctly.
  63   AddReplaceDelta(OrigOffset, -Size);
  64
  65   if (removeLineIfEmpty) {
  66     // Find the line that the remove occurred and if it is completely empty
  67     // remove the line as well.
  68
  69     iterator curLineStart = begin();
  70     unsigned curLineStartOffs = 0;
  71     iterator posI = begin();
  72     for (unsigned i = 0; i != RealOffset; ++i) {
  73       if (*posI == '\n') {
  74         curLineStart = posI;
  75         ++curLineStart;
  76         curLineStartOffs = i + 1;
  77       }
  78       ++posI;
  79     }
  80
  81     unsigned lineSize = 0;
  82     posI = curLineStart;
  83     while (posI != end() && isWhitespace(*posI)) {
  84       ++posI;
  85       ++lineSize;
  86     }
  87     if (posI != end() && *posI == '\n') {
  88       Buffer.erase(curLineStartOffs, lineSize + 1/* + '\n'*/);
  89       AddReplaceDelta(curLineStartOffs, -(lineSize + 1/* + '\n'*/));
  90     }
  91   }
  92 }
  93
  94 void RewriteBuffer::InsertText(unsigned OrigOffset, StringRef Str,
  95                                bool InsertAfter) {
  96
  97   // Nothing to insert, exit early.
  98   if (Str.empty()) return;
  99
 100   unsigned RealOffset = getMappedOffset(OrigOffset, InsertAfter);
 101   Buffer.insert(RealOffset, Str.begin(), Str.end());
 102
 103   // Add a delta so that future changes are offset correctly.
 104   AddInsertDelta(OrigOffset, Str.size());
 105 }
 106
 107 /// ReplaceText - This method replaces a range of characters in the input
 108 /// buffer with a new string.  This is effectively a combined "remove+insert"
 109 /// operation.
 110 void RewriteBuffer::ReplaceText(unsigned OrigOffset, unsigned OrigLength,
 111                                 StringRef NewStr) {
 112   unsigned RealOffset = getMappedOffset(OrigOffset, true);
 113   Buffer.erase(RealOffset, OrigLength);
 114   Buffer.insert(RealOffset, NewStr.begin(), NewStr.end());
 115   if (OrigLength != NewStr.size())
 116     AddReplaceDelta(OrigOffset, NewStr.size() - OrigLength);
 117 }
 118
 119
 120 //===----------------------------------------------------------------------===//
 121 // Rewriter class
 122 //===----------------------------------------------------------------------===//
 123
 124 /// getRangeSize - Return the size in bytes of the specified range if they
 125 /// are in the same file.  If not, this returns -1.
 126 int Rewriter::getRangeSize(const CharSourceRange &Range,
 127                            RewriteOptions opts) const {
 128   if (!isRewritable(Range.getBegin()) ||
 129       !isRewritable(Range.getEnd())) return -1;
 130
 131   FileID StartFileID, EndFileID;
 132   unsigned StartOff, EndOff;
 133
 134   StartOff = getLocationOffsetAndFileID(Range.getBegin(), StartFileID);
 135   EndOff   = getLocationOffsetAndFileID(Range.getEnd(), EndFileID);
 136
 137   if (StartFileID != EndFileID)
 138     return -1;
 139
 140   // If edits have been made to this buffer, the delta between the range may
 141   // have changed.
 142   std::map<FileID, RewriteBuffer>::const_iterator I =
 143     RewriteBuffers.find(StartFileID);
 144   if (I != RewriteBuffers.end()) {
 145     const RewriteBuffer &RB = I->second;
 146     EndOff = RB.getMappedOffset(EndOff, opts.IncludeInsertsAtEndOfRange);
 147     StartOff = RB.getMappedOffset(StartOff, !opts.IncludeInsertsAtBeginOfRange);
 148   }
 149
 150
 151   // Adjust the end offset to the end of the last token, instead of being the
 152   // start of the last token if this is a token range.
 153   if (Range.isTokenRange())
 154     EndOff += Lexer::MeasureTokenLength(Range.getEnd(), *SourceMgr, *LangOpts);
 155
 156   return EndOff-StartOff;
 157 }
 158
 159 int Rewriter::getRangeSize(SourceRange Range, RewriteOptions opts) const {
 160   return getRangeSize(CharSourceRange::getTokenRange(Range), opts);
 161 }
 162
 163
 164 /// getRewrittenText - Return the rewritten form of the text in the specified
 165 /// range.  If the start or end of the range was unrewritable or if they are
 166 /// in different buffers, this returns an empty string.
 167 ///
 168 /// Note that this method is not particularly efficient.
 169 ///
 170 std::string Rewriter::getRewrittenText(SourceRange Range) const {
 171   if (!isRewritable(Range.getBegin()) ||
 172       !isRewritable(Range.getEnd()))
 173     return "";
 174
 175   FileID StartFileID, EndFileID;
 176   unsigned StartOff, EndOff;
 177   StartOff = getLocationOffsetAndFileID(Range.getBegin(), StartFileID);
 178   EndOff   = getLocationOffsetAndFileID(Range.getEnd(), EndFileID);
 179
 180   if (StartFileID != EndFileID)
 181     return ""; // Start and end in different buffers.
 182
 183   // If edits have been made to this buffer, the delta between the range may
 184   // have changed.
 185   std::map<FileID, RewriteBuffer>::const_iterator I =
 186     RewriteBuffers.find(StartFileID);
 187   if (I == RewriteBuffers.end()) {
 188     // If the buffer hasn't been rewritten, just return the text from the input.
 189     const char *Ptr = SourceMgr->getCharacterData(Range.getBegin());
 190
 191     // Adjust the end offset to the end of the last token, instead of being the
 192     // start of the last token.
 193     EndOff += Lexer::MeasureTokenLength(Range.getEnd(), *SourceMgr, *LangOpts);
 194     return std::string(Ptr, Ptr+EndOff-StartOff);
 195   }
 196
 197   const RewriteBuffer &RB = I->second;
 198   EndOff = RB.getMappedOffset(EndOff, true);
 199   StartOff = RB.getMappedOffset(StartOff);
 200
 201   // Adjust the end offset to the end of the last token, instead of being the
 202   // start of the last token.
 203   EndOff += Lexer::MeasureTokenLength(Range.getEnd(), *SourceMgr, *LangOpts);
 204
 205   // Advance the iterators to the right spot, yay for linear time algorithms.
 206   RewriteBuffer::iterator Start = RB.begin();
 207   std::advance(Start, StartOff);
 208   RewriteBuffer::iterator End = Start;
 209   std::advance(End, EndOff-StartOff);
 210
 211   return std::string(Start, End);
 212 }
 213
 214 unsigned Rewriter::getLocationOffsetAndFileID(SourceLocation Loc,
 215                                               FileID &FID) const {
 216   assert(Loc.isValid() && "Invalid location");
 217   std::pair<FileID,unsigned> V = SourceMgr->getDecomposedLoc(Loc);
 218   FID = V.first;
 219   return V.second;
 220 }
 221
 222
 223 /// getEditBuffer - Get or create a RewriteBuffer for the specified FileID.
 224 ///
 225 RewriteBuffer &Rewriter::getEditBuffer(FileID FID) {
 226   std::map<FileID, RewriteBuffer>::iterator I =
 227     RewriteBuffers.lower_bound(FID);
 228   if (I != RewriteBuffers.end() && I->first == FID)
 229     return I->second;
 230   I = RewriteBuffers.insert(I, std::make_pair(FID, RewriteBuffer()));
 231
 232   StringRef MB = SourceMgr->getBufferData(FID);
 233   I->second.Initialize(MB.begin(), MB.end());
 234
 235   return I->second;
 236 }
 237
 238 /// InsertText - Insert the specified string at the specified location in the
 239 /// original buffer.
 240 bool Rewriter::InsertText(SourceLocation Loc, StringRef Str,
 241                           bool InsertAfter, bool indentNewLines) {
 242   if (!isRewritable(Loc)) return true;
 243   FileID FID;
 244   unsigned StartOffs = getLocationOffsetAndFileID(Loc, FID);
 245
 246   SmallString<128> indentedStr;
 247   if (indentNewLines && Str.find('\n') != StringRef::npos) {
 248     StringRef MB = SourceMgr->getBufferData(FID);
 249
 250     unsigned lineNo = SourceMgr->getLineNumber(FID, StartOffs) - 1;
 251     const SrcMgr::ContentCache *
 252         Content = SourceMgr->getSLocEntry(FID).getFile().getContentCache();
 253     unsigned lineOffs = Content->SourceLineCache[lineNo];
 254
 255     // Find the whitespace at the start of the line.
 256     StringRef indentSpace;
 257     {
 258       unsigned i = lineOffs;
 259       while (isWhitespace(MB[i]))
 260         ++i;
 261       indentSpace = MB.substr(lineOffs, i-lineOffs);
 262     }
 263
 264     SmallVector<StringRef, 4> lines;
 265     Str.split(lines, "\n");
 266
 267     for (unsigned i = 0, e = lines.size(); i != e; ++i) {
 268       indentedStr += lines[i];
 269       if (i < e-1) {
 270         indentedStr += '\n';
 271         indentedStr += indentSpace;
 272       }
 273     }
 274     Str = indentedStr.str();
 275   }
 276
 277   getEditBuffer(FID).InsertText(StartOffs, Str, InsertAfter);
 278   return false;
 279 }
 280
 281 bool Rewriter::InsertTextAfterToken(SourceLocation Loc, StringRef Str) {
 282   if (!isRewritable(Loc)) return true;
 283   FileID FID;
 284   unsigned StartOffs = getLocationOffsetAndFileID(Loc, FID);
 285   RewriteOptions rangeOpts;
 286   rangeOpts.IncludeInsertsAtBeginOfRange = false;
 287   StartOffs += getRangeSize(SourceRange(Loc, Loc), rangeOpts);
 288   getEditBuffer(FID).InsertText(StartOffs, Str, /*InsertAfter*/true);
 289   return false;
 290 }
 291
 292 /// RemoveText - Remove the specified text region.
 293 bool Rewriter::RemoveText(SourceLocation Start, unsigned Length,
 294                           RewriteOptions opts) {
 295   if (!isRewritable(Start)) return true;
 296   FileID FID;
 297   unsigned StartOffs = getLocationOffsetAndFileID(Start, FID);
 298   getEditBuffer(FID).RemoveText(StartOffs, Length, opts.RemoveLineIfEmpty);
 299   return false;
 300 }
 301
 302 /// ReplaceText - This method replaces a range of characters in the input
 303 /// buffer with a new string.  This is effectively a combined "remove/insert"
 304 /// operation.
 305 bool Rewriter::ReplaceText(SourceLocation Start, unsigned OrigLength,
 306                            StringRef NewStr) {
 307   if (!isRewritable(Start)) return true;
 308   FileID StartFileID;
 309   unsigned StartOffs = getLocationOffsetAndFileID(Start, StartFileID);
 310
 311   getEditBuffer(StartFileID).ReplaceText(StartOffs, OrigLength, NewStr);
 312   return false;
 313 }
 314
 315 bool Rewriter::ReplaceText(SourceRange range, SourceRange replacementRange) {
 316   if (!isRewritable(range.getBegin())) return true;
 317   if (!isRewritable(range.getEnd())) return true;
 318   if (replacementRange.isInvalid()) return true;
 319   SourceLocation start = range.getBegin();
 320   unsigned origLength = getRangeSize(range);
 321   unsigned newLength = getRangeSize(replacementRange);
 322   FileID FID;
 323   unsigned newOffs = getLocationOffsetAndFileID(replacementRange.getBegin(),
 324                                                 FID);
 325   StringRef MB = SourceMgr->getBufferData(FID);
 326   return ReplaceText(start, origLength, MB.substr(newOffs, newLength));
 327 }
 328
 329 bool Rewriter::IncreaseIndentation(CharSourceRange range,
 330                                    SourceLocation parentIndent) {
 331   if (range.isInvalid()) return true;
 332   if (!isRewritable(range.getBegin())) return true;
 333   if (!isRewritable(range.getEnd())) return true;
 334   if (!isRewritable(parentIndent)) return true;
 335
 336   FileID StartFileID, EndFileID, parentFileID;
 337   unsigned StartOff, EndOff, parentOff;
 338
 339   StartOff = getLocationOffsetAndFileID(range.getBegin(), StartFileID);
 340   EndOff   = getLocationOffsetAndFileID(range.getEnd(), EndFileID);
 341   parentOff = getLocationOffsetAndFileID(parentIndent, parentFileID);
 342
 343   if (StartFileID != EndFileID || StartFileID != parentFileID)
 344     return true;
 345   if (StartOff > EndOff)
 346     return true;
 347
 348   FileID FID = StartFileID;
 349   StringRef MB = SourceMgr->getBufferData(FID);
 350
 351   unsigned parentLineNo = SourceMgr->getLineNumber(FID, parentOff) - 1;
 352   unsigned startLineNo = SourceMgr->getLineNumber(FID, StartOff) - 1;
 353   unsigned endLineNo = SourceMgr->getLineNumber(FID, EndOff) - 1;
 354
 355   const SrcMgr::ContentCache *
 356       Content = SourceMgr->getSLocEntry(FID).getFile().getContentCache();
 357
 358   // Find where the lines start.
 359   unsigned parentLineOffs = Content->SourceLineCache[parentLineNo];
 360   unsigned startLineOffs = Content->SourceLineCache[startLineNo];
 361
 362   // Find the whitespace at the start of each line.
 363   StringRef parentSpace, startSpace;
 364   {
 365     unsigned i = parentLineOffs;
 366     while (isWhitespace(MB[i]))
 367       ++i;
 368     parentSpace = MB.substr(parentLineOffs, i-parentLineOffs);
 369
 370     i = startLineOffs;
 371     while (isWhitespace(MB[i]))
 372       ++i;
 373     startSpace = MB.substr(startLineOffs, i-startLineOffs);
 374   }
 375   if (parentSpace.size() >= startSpace.size())
 376     return true;
 377   if (!startSpace.startswith(parentSpace))
 378     return true;
 379
 380   StringRef indent = startSpace.substr(parentSpace.size());
 381
 382   // Indent the lines between start/end offsets.
 383   RewriteBuffer &RB = getEditBuffer(FID);
 384   for (unsigned lineNo = startLineNo; lineNo <= endLineNo; ++lineNo) {
 385     unsigned offs = Content->SourceLineCache[lineNo];
 386     unsigned i = offs;
 387     while (isWhitespace(MB[i]))
 388       ++i;
 389     StringRef origIndent = MB.substr(offs, i-offs);
 390     if (origIndent.startswith(startSpace))
 391       RB.InsertText(offs, indent, /*InsertAfter=*/false);
 392   }
 393
 394   return false;
 395 }
 396
 397 namespace {
 398 // A wrapper for a file stream that atomically overwrites the target.
 399 //
 400 // Creates a file output stream for a temporary file in the constructor,
 401 // which is later accessible via getStream() if ok() return true.
 402 // Flushes the stream and moves the temporary file to the target location
 403 // in the destructor.
 404 class AtomicallyMovedFile {
 405 public:
 406   AtomicallyMovedFile(DiagnosticsEngine &Diagnostics, StringRef Filename,
 407                       bool &AllWritten)
 408     : Diagnostics(Diagnostics), Filename(Filename), AllWritten(AllWritten) {
 409     TempFilename = Filename;
 410     TempFilename += "-%%%%%%%%";
 411     int FD;
 412     if (llvm::sys::fs::createUniqueFile(TempFilename.str(), FD, TempFilename)) {
 413       AllWritten = false;
 414       Diagnostics.Report(clang::diag::err_unable_to_make_temp)
 415         << TempFilename;
 416     } else {
 417       FileStream.reset(new llvm::raw_fd_ostream(FD, /*shouldClose=*/true));
 418     }
 419   }
 420
 421   ~AtomicallyMovedFile() {
 422     if (!ok()) return;
 423
 424     FileStream->flush();
 425 #ifdef LLVM_ON_WIN32
 426     // Win32 does not allow rename/removing opened files.
 427     FileStream.reset();
 428 #endif
 429     if (std::error_code ec =
 430             llvm::sys::fs::rename(TempFilename.str(), Filename)) {
 431       AllWritten = false;
 432       Diagnostics.Report(clang::diag::err_unable_to_rename_temp)
 433         << TempFilename << Filename << ec.message();
 434       // If the remove fails, there's not a lot we can do - this is already an
 435       // error.
 436       llvm::sys::fs::remove(TempFilename.str());
 437     }
 438   }
 439
 440   bool ok() { return (bool)FileStream; }
 441   raw_ostream &getStream() { return *FileStream; }
 442
 443 private:
 444   DiagnosticsEngine &Diagnostics;
 445   StringRef Filename;
 446   SmallString<128> TempFilename;
 447   std::unique_ptr<llvm::raw_fd_ostream> FileStream;
 448   bool &AllWritten;
 449 };
 450 } // end anonymous namespace
 451
 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 }