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// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "net/disk_cache/cache_util.h"
#include <limits>
#include "base/files/file_enumerator.h"
#include "base/files/file_util.h"
#include "base/location.h"
#include "base/strings/string_util.h"
#include "base/strings/stringprintf.h"
#include "base/strings/utf_string_conversions.h"
#include "base/threading/thread_restrictions.h"
#include "base/threading/worker_pool.h"
namespace {
const int kMaxOldFolders = 100;
// Returns a fully qualified name from path and name, using a given name prefix
// and index number. For instance, if the arguments are "/foo", "bar" and 5, it
// will return "/foo/old_bar_005".
base::FilePath GetPrefixedName(const base::FilePath& path,
const std::string& name,
int index) {
std::string tmp = base::StringPrintf("%s%s_%03d", "old_",
name.c_str(), index);
return path.AppendASCII(tmp);
}
// This is a simple callback to cleanup old caches.
void CleanupCallback(const base::FilePath& path, const std::string& name) {
for (int i = 0; i < kMaxOldFolders; i++) {
base::FilePath to_delete = GetPrefixedName(path, name, i);
disk_cache::DeleteCache(to_delete, true);
}
}
// Returns a full path to rename the current cache, in order to delete it. path
// is the current folder location, and name is the current folder name.
base::FilePath GetTempCacheName(const base::FilePath& path,
const std::string& name) {
// We'll attempt to have up to kMaxOldFolders folders for deletion.
for (int i = 0; i < kMaxOldFolders; i++) {
base::FilePath to_delete = GetPrefixedName(path, name, i);
if (!base::PathExists(to_delete))
return to_delete;
}
return base::FilePath();
}
int64_t PreferredCacheSizeInternal(int64_t available) {
using disk_cache::kDefaultCacheSize;
// Return 80% of the available space if there is not enough space to use
// kDefaultCacheSize.
if (available < kDefaultCacheSize * 10 / 8)
return available * 8 / 10;
// Return kDefaultCacheSize if it uses 10% to 80% of the available space.
if (available < kDefaultCacheSize * 10)
return kDefaultCacheSize;
// Return 10% of the available space if the target size
// (2.5 * kDefaultCacheSize) is more than 10%.
if (available < static_cast<int64_t>(kDefaultCacheSize) * 25)
return available / 10;
// Return the target size (2.5 * kDefaultCacheSize) if it uses 10% to 1%
// of the available space.
if (available < static_cast<int64_t>(kDefaultCacheSize) * 250)
return kDefaultCacheSize * 5 / 2;
// Return 1% of the available space.
return available / 100;
}
} // namespace
namespace disk_cache {
const int kDefaultCacheSize = 80 * 1024 * 1024;
void DeleteCache(const base::FilePath& path, bool remove_folder) {
if (remove_folder) {
if (!base::DeleteFile(path, /* recursive */ true))
LOG(WARNING) << "Unable to delete cache folder.";
return;
}
base::FileEnumerator iter(
path,
/* recursive */ false,
base::FileEnumerator::FILES | base::FileEnumerator::DIRECTORIES);
for (base::FilePath file = iter.Next(); !file.value().empty();
file = iter.Next()) {
if (!base::DeleteFile(file, /* recursive */ true)) {
LOG(WARNING) << "Unable to delete cache.";
return;
}
}
}
// In order to process a potentially large number of files, we'll rename the
// cache directory to old_ + original_name + number, (located on the same parent
// directory), and use a worker thread to delete all the files on all the stale
// cache directories. The whole process can still fail if we are not able to
// rename the cache directory (for instance due to a sharing violation), and in
// that case a cache for this profile (on the desired path) cannot be created.
bool DelayedCacheCleanup(const base::FilePath& full_path) {
// GetTempCacheName() and MoveCache() use synchronous file
// operations.
base::ThreadRestrictions::ScopedAllowIO allow_io;
base::FilePath current_path = full_path.StripTrailingSeparators();
base::FilePath path = current_path.DirName();
base::FilePath name = current_path.BaseName();
#if defined(OS_POSIX)
std::string name_str = name.value();
#elif defined(OS_WIN)
// We created this file so it should only contain ASCII.
std::string name_str = base::UTF16ToASCII(name.value());
#endif
base::FilePath to_delete = GetTempCacheName(path, name_str);
if (to_delete.empty()) {
LOG(ERROR) << "Unable to get another cache folder";
return false;
}
if (!disk_cache::MoveCache(full_path, to_delete)) {
LOG(ERROR) << "Unable to move cache folder " << full_path.value() << " to "
<< to_delete.value();
return false;
}
base::WorkerPool::PostTask(
FROM_HERE, base::Bind(&CleanupCallback, path, name_str), true);
return true;
}
// Returns the preferred maximum number of bytes for the cache given the
// number of available bytes.
int PreferredCacheSize(int64_t available) {
if (available < 0)
return kDefaultCacheSize;
// Limit cache size to somewhat less than kint32max to avoid potential
// integer overflows in cache backend implementations.
DCHECK_LT(kDefaultCacheSize * 4, std::numeric_limits<int32_t>::max());
return static_cast<int32_t>(
std::min(PreferredCacheSizeInternal(available),
static_cast<int64_t>(kDefaultCacheSize * 4)));
}
} // namespace disk_cache
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