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/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() {
  delete Buffer;
}

/// 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 ? Buffer->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 ? (unsigned) Buffer->getBufferSize()
                : (unsigned) Entry->getSize();
}

void ContentCache::replaceBuffer(const llvm::MemoryBuffer *B) {
  assert(B != Buffer);
  
  delete Buffer;
  Buffer = B;
}

const llvm::MemoryBuffer *ContentCache::getBuffer(Diagnostic &Diag,
                                                  bool *Invalid) const {
  if (Invalid)
    *Invalid = false;
      
  // Lazily create the Buffer for ContentCaches that wrap files.
  if (!Buffer && Entry) {
    std::string ErrorStr;
    struct stat FileInfo;
    Buffer = MemoryBuffer::getFile(Entry->getName(), &ErrorStr,
                                   Entry->getSize(), &FileInfo);

    // 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) {
      const llvm::StringRef FillStr("<<<MISSING SOURCE FILE>>>\n");
      Buffer = MemoryBuffer::getNewMemBuffer(Entry->getSize(), "<invalid>");
      char *Ptr = const_cast<char*>(Buffer->getBufferStart());
      for (unsigned i = 0, e = Entry->getSize(); i != e; ++i)
        Ptr[i] = FillStr[i % FillStr.size()];
      Diag.Report(diag::err_cannot_open_file)
        << Entry->getName() << ErrorStr;
      if (Invalid)
        *Invalid = true;
    } else {
      // Check that the file's size and modification time is the same as 
      // in the file entry (which may have come from a stat cache).
      if (FileInfo.st_size != Entry->getSize()) {
        Diag.Report(diag::err_file_size_changed)
          << Entry->getName() << (unsigned)Entry->getSize() 
          << (unsigned)FileInfo.st_size;
        if (Invalid)
          *Invalid = true;
      } else if