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      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 #include "chrome/browser/media_galleries/fileapi/mtp_device_map_service.h"
      6 
      7 #include <string>
      8 #include <utility>
      9 
     10 #include "base/stl_util.h"
     11 #include "chrome/browser/media_galleries/fileapi/mtp_device_async_delegate.h"
     12 #include "content/public/browser/browser_thread.h"
     13 #include "storage/browser/fileapi/external_mount_points.h"
     14 
     15 namespace {
     16 
     17 base::LazyInstance<MTPDeviceMapService> g_mtp_device_map_service =
     18     LAZY_INSTANCE_INITIALIZER;
     19 
     20 }  // namespace
     21 
     22 // static
     23 MTPDeviceMapService* MTPDeviceMapService::GetInstance() {
     24   return g_mtp_device_map_service.Pointer();
     25 }
     26 
     27 void MTPDeviceMapService::RegisterMTPFileSystem(
     28     const base::FilePath::StringType& device_location,
     29     const std::string& fsid) {
     30   DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
     31 
     32   if (!ContainsKey(mtp_device_usage_map_, device_location)) {
     33     // Note that this initializes the delegate asynchronously, but since
     34     // the delegate will only be used from the IO thread, it is guaranteed
     35     // to be created before use of it expects it to be there.
     36     CreateMTPDeviceAsyncDelegate(device_location,
     37         base::Bind(&MTPDeviceMapService::AddAsyncDelegate,
     38                    base::Unretained(this), device_location));
     39     mtp_device_usage_map_[device_location] = 0;
     40   }
     41 
     42   mtp_device_usage_map_[device_location]++;
     43   mtp_device_map_[fsid] = device_location;
     44 }
     45 
     46 void MTPDeviceMapService::RevokeMTPFileSystem(const std::string& fsid) {
     47   DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
     48 
     49   MTPDeviceFileSystemMap::iterator it = mtp_device_map_.find(fsid);
     50   if (it != mtp_device_map_.end()) {
     51     base::FilePath::StringType device_location = it->second;
     52     mtp_device_map_.erase(it);
     53     MTPDeviceUsageMap::iterator delegate_it =
     54         mtp_device_usage_map_.find(device_location);
     55     DCHECK(delegate_it != mtp_device_usage_map_.end());
     56     mtp_device_usage_map_[device_location]--;
     57     if (mtp_device_usage_map_[device_location] == 0) {
     58       mtp_device_usage_map_.erase(delegate_it);
     59       RemoveAsyncDelegate(device_location);
     60     }
     61   }
     62 }
     63 
     64 void MTPDeviceMapService::AddAsyncDelegate(
     65     const base::FilePath::StringType& device_location,
     66     MTPDeviceAsyncDelegate* delegate) {
     67   DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
     68   DCHECK(delegate);
     69   DCHECK(!device_location.empty());
     70   if (ContainsKey(async_delegate_map_, device_location))
     71     return;
     72   async_delegate_map_[device_location] = delegate;
     73 }
     74 
     75 void MTPDeviceMapService::RemoveAsyncDelegate(
     76     const base::FilePath::StringType& device_location) {
     77   DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
     78   AsyncDelegateMap::iterator it = async_delegate_map_.find(device_location);
     79   DCHECK(it != async_delegate_map_.end());
     80   it->second->CancelPendingTasksAndDeleteDelegate();
     81   async_delegate_map_.erase(it);
     82 }
     83 
     84 MTPDeviceAsyncDelegate* MTPDeviceMapService::GetMTPDeviceAsyncDelegate(
     85     const std::string& filesystem_id) {
     86   DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
     87   base::FilePath device_path;
     88   if (!storage::ExternalMountPoints::GetSystemInstance()->GetRegisteredPath(
     89           filesystem_id, &device_path)) {
     90     return NULL;
     91   }
     92 
     93   const base::FilePath::StringType& device_location = device_path.value();
     94   DCHECK(!device_location.empty());
     95   AsyncDelegateMap::const_iterator it =
     96       async_delegate_map_.find(device_location);
     97   return (it != async_delegate_map_.end()) ? it->second : NULL;
     98 }
     99 
    100 MTPDeviceMapService::MTPDeviceMapService() {
    101 }
    102 
    103 MTPDeviceMapService::~MTPDeviceMapService() {
    104   DCHECK(mtp_device_usage_map_.empty());
    105 }
    106