net/disk_cache/cache_util.cc

   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 "net/disk_cache/cache_util.h"
   6
   7 #include "base/file_util.h"
   8 #include "base/files/file_enumerator.h"
   9 #include "base/location.h"
  10 #include "base/strings/string_util.h"
  11 #include "base/strings/stringprintf.h"
  12 #include "base/threading/thread_restrictions.h"
  13 #include "base/threading/worker_pool.h"
  14
  15 namespace {
  16
  17 const int kMaxOldFolders = 100;
  18
  19 // Returns a fully qualified name from path and name, using a given name prefix
  20 // and index number. For instance, if the arguments are "/foo", "bar" and 5, it
  21 // will return "/foo/old_bar_005".
  22 base::FilePath GetPrefixedName(const base::FilePath& path,
  23                                const std::string& name,
  24                                int index) {
  25   std::string tmp = base::StringPrintf("%s%s_%03d", "old_",
  26                                        name.c_str(), index);
  27   return path.AppendASCII(tmp);
  28 }
  29
  30 // This is a simple callback to cleanup old caches.
  31 void CleanupCallback(const base::FilePath& path, const std::string& name) {
  32   for (int i = 0; i < kMaxOldFolders; i++) {
  33     base::FilePath to_delete = GetPrefixedName(path, name, i);
  34     disk_cache::DeleteCache(to_delete, true);
  35   }
  36 }
  37
  38 // Returns a full path to rename the current cache, in order to delete it. path
  39 // is the current folder location, and name is the current folder name.
  40 base::FilePath GetTempCacheName(const base::FilePath& path,
  41                                 const std::string& name) {
  42   // We'll attempt to have up to kMaxOldFolders folders for deletion.
  43   for (int i = 0; i < kMaxOldFolders; i++) {
  44     base::FilePath to_delete = GetPrefixedName(path, name, i);
  45     if (!base::PathExists(to_delete))
  46       return to_delete;
  47   }
  48   return base::FilePath();
  49 }
  50
  51 }  // namespace
  52
  53 namespace disk_cache {
  54
  55 void DeleteCache(const base::FilePath& path, bool remove_folder) {
  56   if (remove_folder) {
  57     if (!base::DeleteFile(path, /* recursive */ true))
  58       LOG(WARNING) << "Unable to delete cache folder.";
  59     return;
  60   }
  61
  62   base::FileEnumerator iter(
  63       path,
  64       /* recursive */ false,
  65       base::FileEnumerator::FILES | base::FileEnumerator::DIRECTORIES);
  66   for (base::FilePath file = iter.Next(); !file.value().empty();
  67        file = iter.Next()) {
  68     if (!base::DeleteFile(file, /* recursive */ true)) {
  69       LOG(WARNING) << "Unable to delete cache.";
  70       return;
  71     }
  72   }
  73 }
  74
  75 // In order to process a potentially large number of files, we'll rename the
  76 // cache directory to old_ + original_name + number, (located on the same parent
  77 // directory), and use a worker thread to delete all the files on all the stale
  78 // cache directories. The whole process can still fail if we are not able to
  79 // rename the cache directory (for instance due to a sharing violation), and in
  80 // that case a cache for this profile (on the desired path) cannot be created.
  81 bool DelayedCacheCleanup(const base::FilePath& full_path) {
  82   // GetTempCacheName() and MoveCache() use synchronous file
  83   // operations.
  84   base::ThreadRestrictions::ScopedAllowIO allow_io;
  85
  86   base::FilePath current_path = full_path.StripTrailingSeparators();
  87
  88   base::FilePath path = current_path.DirName();
  89   base::FilePath name = current_path.BaseName();
  90 #if defined(OS_POSIX)
  91   std::string name_str = name.value();
  92 #elif defined(OS_WIN)
  93   // We created this file so it should only contain ASCII.
  94   std::string name_str = WideToASCII(name.value());
  95 #endif
  96
  97   base::FilePath to_delete = GetTempCacheName(path, name_str);
  98   if (to_delete.empty()) {
  99     LOG(ERROR) << "Unable to get another cache folder";
 100     return false;
 101   }
 102
 103   if (!disk_cache::MoveCache(full_path, to_delete)) {
 104     LOG(ERROR) << "Unable to move cache folder " << full_path.value() << " to "
 105                << to_delete.value();
 106     return false;
 107   }
 108
 109   base::WorkerPool::PostTask(
 110       FROM_HERE, base::Bind(&CleanupCallback, path, name_str), true);
 111   return true;
 112 }
 113
 114 }  // namespace disk_cache