path: root/lib/Basic/SourceManager.cpp

//===--- SourceManager.cpp - Track and cache source files -----------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
//  This file implements the SourceManager interface.
//
//===----------------------------------------------------------------------===//

#include "clang/Basic/SourceManager.h"
#include "clang/Basic/SourceManagerInternals.h"
#include "clang/Basic/Diagnostic.h"
#include "clang/Basic/FileManager.h"
#include "llvm/ADT/StringSwitch.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/MemoryBuffer.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/System/Path.h"
#include <algorithm>
#include <string>
#include <cstring>

using namespace clang;
using namespace SrcMgr;
using llvm::MemoryBuffer;

//===----------------------------------------------------------------------===//
// SourceManager Helper Classes
//===----------------------------------------------------------------------===//

ContentCache::~ContentCache() {
  if (shouldFreeBuffer())
    delete Buffer.getPointer();
}

/// getSizeBytesMapped - Returns the number of bytes actually mapped for
///  this ContentCache.  This can be 0 if the MemBuffer was not actually
///  instantiated.
unsigned ContentCache::getSizeBytesMapped() const {
  return Buffer.getPointer() ? Buffer.getPointer()->getBufferSize() : 0;
}

/// getSize - Returns the size of the content encapsulated by this ContentCache.
///  This can be the size of the source file or the size of an arbitrary
///  scratch buffer.  If the ContentCache encapsulates a source file, that
///  file is not lazily brought in from disk to satisfy this query.
unsigned ContentCache::getSize() const {
  return Buffer.getPointer() ? (unsigned) Buffer.getPointer()->getBufferSize()
                             : (unsigned) Entry->getSize();
}

void ContentCache::replaceBuffer(const llvm::MemoryBuffer *B,
                                 bool DoNotFree) {
  assert(B != Buffer.getPointer());
  
  if (shouldFreeBuffer())
    delete Buffer.getPointer();
  Buffer.setPointer(B);
  Buffer.setInt(DoNotFree? DoNotFreeFlag : 0);
}

const llvm::MemoryBuffer *ContentCache::getBuffer(Diagnostic &Diag,
                                                  const SourceManager &SM,
                                                  SourceLocation Loc,
                                                  bool *Invalid) const {
  if (Invalid)
    *Invalid = false;
      
  // Lazily create the Buffer for ContentCaches that wrap files.
  if (!Buffer.getPointer() && Entry) {
    std::string ErrorStr;
    Buffer.setPointer(SM.getFileManager().getBufferForFile(Entry, &ErrorStr));

    // If we were unable to open the file, then we are in an inconsistent
    // situation where the content cache referenced a file which no longer
    // exists. Most likely, we were using a stat cache with an invalid entry but
    // the file could also have been removed during processing. Since we can't
    // really deal with this situation, just create an empty buffer.
    //
    // FIXME: This is definitely not ideal, but our immediate clients can't
    // currently handle returning a null entry here. Ideally we should detect
    // that we are in an inconsistent situation and error out as quickly as
    // possible.
    if (!Buffer.getPointer()) {
      const