зеркало из https://github.com/microsoft/clang-1.git
233 строки
8.2 KiB
C++
233 строки
8.2 KiB
C++
//===--- Rewriter.cpp - Code rewriting interface --------------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file was developed by Chris Lattner and is distributed under
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// the University of Illinois Open Source License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file defines the Rewriter class, which is used for code
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// transformations.
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//
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//===----------------------------------------------------------------------===//
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#include "clang/Rewrite/Rewriter.h"
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#include "clang/AST/Stmt.h"
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#include "clang/Lex/Lexer.h"
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#include "clang/Basic/SourceManager.h"
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#include <sstream>
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using namespace clang;
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/// getMappedOffset - Given an offset into the original SourceBuffer that this
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/// RewriteBuffer is based on, map it into the offset space of the
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/// RewriteBuffer.
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unsigned RewriteBuffer::getMappedOffset(unsigned OrigOffset,
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bool AfterInserts) const {
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unsigned ResultOffset = OrigOffset;
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unsigned DeltaIdx = 0;
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// Move past any deltas that are relevant.
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// FIXME: binary search.
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for (; DeltaIdx != Deltas.size() &&
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Deltas[DeltaIdx].FileLoc < OrigOffset; ++DeltaIdx)
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ResultOffset += Deltas[DeltaIdx].Delta;
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if (AfterInserts && DeltaIdx != Deltas.size() &&
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OrigOffset == Deltas[DeltaIdx].FileLoc)
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ResultOffset += Deltas[DeltaIdx].Delta;
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return ResultOffset;
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}
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/// AddDelta - When a change is made that shifts around the text buffer, this
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/// method is used to record that info.
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void RewriteBuffer::AddDelta(unsigned OrigOffset, int Change) {
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assert(Change != 0 && "Not changing anything");
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unsigned DeltaIdx = 0;
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// Skip over any unrelated deltas.
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for (; DeltaIdx != Deltas.size() &&
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Deltas[DeltaIdx].FileLoc < OrigOffset; ++DeltaIdx)
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;
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// If there is no a delta for this offset, insert a new delta record.
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if (DeltaIdx == Deltas.size() || OrigOffset != Deltas[DeltaIdx].FileLoc) {
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// If this is a removal, check to see if this can be folded into
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// a delta at the end of the deletion. For example, if we have:
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// ABCXDEF (X inserted after C) and delete C, we want to end up with no
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// delta because X basically replaced C.
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if (Change < 0 && DeltaIdx != Deltas.size() &&
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OrigOffset-Change == Deltas[DeltaIdx].FileLoc) {
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// Adjust the start of the delta to be the start of the deleted region.
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Deltas[DeltaIdx].FileLoc += Change;
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Deltas[DeltaIdx].Delta += Change;
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// If the delta becomes a noop, remove it.
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if (Deltas[DeltaIdx].Delta == 0)
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Deltas.erase(Deltas.begin()+DeltaIdx);
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return;
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}
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// Otherwise, create an entry and return.
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Deltas.insert(Deltas.begin()+DeltaIdx,
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SourceDelta::get(OrigOffset, Change));
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return;
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}
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// Otherwise, we found a delta record at this offset, adjust it.
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Deltas[DeltaIdx].Delta += Change;
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// If it is now dead, remove it.
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if (Deltas[DeltaIdx].Delta)
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Deltas.erase(Deltas.begin()+DeltaIdx);
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}
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void RewriteBuffer::RemoveText(unsigned OrigOffset, unsigned Size) {
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// Nothing to remove, exit early.
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if (Size == 0) return;
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unsigned RealOffset = getMappedOffset(OrigOffset, true);
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assert(RealOffset+Size < Buffer.size() && "Invalid location");
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// Remove the dead characters.
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Buffer.erase(Buffer.begin()+RealOffset, Buffer.begin()+RealOffset+Size);
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// Add a delta so that future changes are offset correctly.
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AddDelta(OrigOffset, -Size);
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}
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void RewriteBuffer::InsertText(unsigned OrigOffset,
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const char *StrData, unsigned StrLen) {
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// Nothing to insert, exit early.
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if (StrLen == 0) return;
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unsigned RealOffset = getMappedOffset(OrigOffset, true);
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assert(RealOffset <= Buffer.size() && "Invalid location");
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// Remove the dead characters.
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Buffer.insert(Buffer.begin()+RealOffset, StrData, StrData+StrLen);
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// Add a delta so that future changes are offset correctly.
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AddDelta(OrigOffset, StrLen);
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}
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/// ReplaceText - This method replaces a range of characters in the input
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/// buffer with a new string. This is effectively a combined "remove/insert"
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/// operation.
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void RewriteBuffer::ReplaceText(unsigned OrigOffset, unsigned OrigLength,
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const char *NewStr, unsigned NewLength) {
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unsigned RealOffset = getMappedOffset(OrigOffset);
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assert(RealOffset+OrigLength <= Buffer.size() && "Invalid location");
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// Overwrite the common piece.
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memcpy(&Buffer[RealOffset], NewStr, std::min(OrigLength, NewLength));
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// If replacing without shifting around, just overwrite the text.
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if (OrigLength == NewLength)
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return;
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// If inserting more than existed before, this is like an insertion.
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if (NewLength > OrigLength) {
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Buffer.insert(Buffer.begin()+RealOffset+OrigLength,
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NewStr+OrigLength, NewStr+NewLength);
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} else {
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// If insertion less than existed before, this is like a removal.
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Buffer.erase(Buffer.begin()+RealOffset+NewLength,
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Buffer.begin()+RealOffset+OrigLength);
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}
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AddDelta(OrigOffset, NewLength-OrigLength);
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}
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//===----------------------------------------------------------------------===//
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// Rewriter class
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//===----------------------------------------------------------------------===//
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/// getRangeSize - Return the size in bytes of the specified range if they
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/// are in the same file. If not, this returns -1.
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int Rewriter::getRangeSize(SourceRange Range) const {
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if (!isRewritable(Range.getBegin()) ||
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!isRewritable(Range.getEnd())) return -1;
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unsigned StartOff, StartFileID;
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unsigned EndOff , EndFileID;
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StartOff = getLocationOffsetAndFileID(Range.getBegin(), StartFileID);
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EndOff = getLocationOffsetAndFileID(Range.getEnd(), EndFileID);
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if (StartFileID != EndFileID)
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return -1;
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// Adjust the end offset to the end of the last token, instead of being the
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// start of the last token.
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EndOff += Lexer::MeasureTokenLength(Range.getEnd(), *SourceMgr);
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return EndOff-StartOff;
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}
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unsigned Rewriter::getLocationOffsetAndFileID(SourceLocation Loc,
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unsigned &FileID) const {
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std::pair<unsigned,unsigned> V = SourceMgr->getDecomposedFileLoc(Loc);
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FileID = V.first;
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return V.second;
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}
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/// getEditBuffer - Get or create a RewriteBuffer for the specified FileID.
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///
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RewriteBuffer &Rewriter::getEditBuffer(unsigned FileID) {
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std::map<unsigned, RewriteBuffer>::iterator I =
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RewriteBuffers.lower_bound(FileID);
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if (I != RewriteBuffers.end() && I->first == FileID)
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return I->second;
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I = RewriteBuffers.insert(I, std::make_pair(FileID, RewriteBuffer()));
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std::pair<const char*, const char*> MB = SourceMgr->getBufferData(FileID);
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I->second.Initialize(MB.first, MB.second);
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return I->second;
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}
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/// RemoveText - Remove the specified text region. This method is only valid
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/// on a rewritable source location.
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void Rewriter::RemoveText(SourceLocation Start, unsigned Length) {
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unsigned FileID;
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unsigned StartOffs = getLocationOffsetAndFileID(Start, FileID);
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getEditBuffer(FileID).RemoveText(StartOffs, Length);
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}
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/// ReplaceText - This method replaces a range of characters in the input
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/// buffer with a new string. This is effectively a combined "remove/insert"
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/// operation.
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void Rewriter::ReplaceText(SourceLocation Start, unsigned OrigLength,
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const char *NewStr, unsigned NewLength) {
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assert(isRewritable(Start) && "Not a rewritable location!");
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unsigned StartFileID;
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unsigned StartOffs = getLocationOffsetAndFileID(Start, StartFileID);
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getEditBuffer(StartFileID).ReplaceText(StartOffs, OrigLength,
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NewStr, NewLength);
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}
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/// ReplaceStmt - This replaces a Stmt/Expr with another, using the pretty
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/// printer to generate the replacement code. This returns true if the input
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/// could not be rewritten, or false if successful.
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bool Rewriter::ReplaceStmt(Stmt *From, Stmt *To) {
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// Measaure the old text.
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int Size = getRangeSize(From->getSourceRange());
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if (Size == -1)
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return true;
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// Get the new text.
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std::ostringstream S;
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To->printPretty(S);
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const std::string &Str = S.str();
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ReplaceText(From->getLocStart(), Size, &Str[0], Str.size());
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return false;
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}
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