1    :  // Copyright 2012 Google Inc. All Rights Reserved.
   2    :  //
   3    :  // Licensed under the Apache License, Version 2.0 (the "License");
   4    :  // you may not use this file except in compliance with the License.
   5    :  // You may obtain a copy of the License at
   6    :  //
   7    :  //     http://www.apache.org/licenses/LICENSE-2.0
   8    :  //
   9    :  // Unless required by applicable law or agreed to in writing, software
  10    :  // distributed under the License is distributed on an "AS IS" BASIS,
  11    :  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  12    :  // See the License for the specific language governing permissions and
  13    :  // limitations under the License.
  14    :  
  15    :  #ifndef SYZYGY_PDB_PDB_FILE_STREAM_H_
  16    :  #define SYZYGY_PDB_PDB_FILE_STREAM_H_
  17    :  
  18    :  #include <stdio.h>
  19    :  
  20    :  #include "base/basictypes.h"
  21    :  #include "base/memory/ref_counted.h"
  22    :  #include "syzygy/pdb/pdb_stream.h"
  23    :  
  24    :  namespace pdb {
  25    :  
  26    :  // A reference counted FILE pointer object.
  27    :  // NOTE: This is not thread safe for a variety of reasons.
  28    :  class RefCountedFILE : public base::RefCounted<RefCountedFILE> {
  29    :   public:
  30  E :    explicit RefCountedFILE(FILE* file) : file_(file) { }
  31    :  
  32    :    // @returns the file pointer being reference counted.
  33  E :    FILE* file() { return file_; }
  34    :  
  35    :   private:
  36    :    friend base::RefCounted<RefCountedFILE>;
  37    :  
  38    :    // We disallow access to the destructor to enforce the use of reference
  39    :    // counting pointers.
  40  E :    ~RefCountedFILE() {
  41  E :      if (file_)
  42  E :        ::fclose(file_);
  43  E :    }
  44    :  
  45    :    FILE* file_;
  46    :  
  47    :    DISALLOW_COPY_AND_ASSIGN(RefCountedFILE);
  48    :  };
  49    :  
  50    :  // This class represents a PDB stream on disk.
  51    :  class PdbFileStream : public PdbStream {
  52    :   public:
  53    :    // Constructor.
  54    :    // @param file the reference counted file housing this stream.
  55    :    // @param length the length of this stream.
  56    :    // @param pages the indices of the pages that make up this stream in the file.
  57    :    //     A copy is made of the data so the pointer need not remain valid
  58    :    //     beyond the constructor. The length of this array is implicit in the
  59    :    //     stream length and the page size.
  60    :    // @param page_size the size of the pages, in bytes.
  61    :    PdbFileStream(RefCountedFILE* file,
  62    :                  size_t length,
  63    :                  const uint32* pages,
  64    :                  size_t page_size);
  65    :  
  66    :    // PdbStream implementation.
  67    :    bool ReadBytes(void* dest, size_t count, size_t* bytes_read);
  68    :  
  69    :   protected:
  70    :    // Protected to enforce reference counted pointers at compile time.
  71    :    virtual ~PdbFileStream();
  72    :  
  73    :    // Read @p count bytes from @p offset byte offset from page @p page_num and
  74    :    // store them in @p dest.
  75    :    bool ReadFromPage(void* dest, uint32 page_num, size_t offset, size_t count);
  76    :  
  77    :   private:
  78    :    // The handle to the open PDB file. This is reference counted so ownership of
  79    :    // that streams can outlive the PdbReader that created them.
  80    :    scoped_refptr<RefCountedFILE> file_;
  81    :  
  82    :    // The list of pages in the pdb PDB that make up this stream.
  83    :    std::vector<uint32> pages_;
  84    :  
  85    :    // The size of pages within the stream.
  86    :    size_t page_size_;
  87    :  
  88    :    DISALLOW_COPY_AND_ASSIGN(PdbFileStream);
  89    :  };
  90    :  
  91    :  }  // namespace pdb
  92    :  
  93    :  #endif  // SYZYGY_PDB_PDB_FILE_STREAM_H_