native_client_sdk/src/libraries/nacl_io/inode_pool.h

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef LIBRARIES_NACL_IO_INODE_POOL_H_
   6 #define LIBRARIES_NACL_IO_INODE_POOL_H_
   7
   8 #include <stdlib.h>
   9 #include <vector>
  10
  11 #include "nacl_io/osstat.h"
  12 #include "pthread.h"
  13 #include "sdk_util/auto_lock.h"
  14
  15 namespace nacl_io {
  16
  17 class INodePool {
  18  public:
  19   INodePool() : num_nodes_(0), max_nodes_(0) {}
  20
  21   ino_t Acquire() {
  22     AUTO_LOCK(lock_);
  23     const int INO_CNT = 8;
  24
  25     // If we run out of INO numbers, then allocate 8 more
  26     if (inos_.size() == 0) {
  27       max_nodes_ += INO_CNT;
  28       // Add eight more to the stack in reverse order, offset by 1
  29       // since '0' refers to no INO.
  30       for (int a = 0; a < INO_CNT; a++) {
  31         inos_.push_back(max_nodes_ - a);
  32       }
  33     }
  34
  35     // Return the INO at the top of the stack.
  36     int val = inos_.back();
  37     inos_.pop_back();
  38     num_nodes_++;
  39     return val;
  40   }
  41
  42   void Release(ino_t ino) {
  43     AUTO_LOCK(lock_);
  44     inos_.push_back(ino);
  45     num_nodes_--;
  46   }
  47
  48   size_t size() const { return num_nodes_; }
  49   size_t capacity() const { return max_nodes_; }
  50
  51  private:
  52   size_t num_nodes_;
  53   size_t max_nodes_;
  54   std::vector<ino_t> inos_;
  55   sdk_util::SimpleLock lock_;
  56 };
  57
  58 }  // namespace nacl_io
  59
  60 #endif  // LIBRARIES_NACL_IO_INODE_POOL_H_