blob: afaf9d26aa901722ec86d0ba93e0cbd1608fe2be [file] [log] [blame]
/*
* libjingle
* Copyright 2004--2005, Google Inc.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
* EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <time.h>
#ifdef WIN32
#include "talk/base/win32.h"
#endif
#include "talk/base/common.h"
#include "talk/base/diskcache.h"
#include "talk/base/fileutils.h"
#include "talk/base/pathutils.h"
#include "talk/base/stream.h"
#include "talk/base/stringencode.h"
#include "talk/base/stringutils.h"
#ifdef _DEBUG
#define TRANSPARENT_CACHE_NAMES 1
#else // !_DEBUG
#define TRANSPARENT_CACHE_NAMES 0
#endif // !_DEBUG
namespace talk_base {
class DiskCache;
///////////////////////////////////////////////////////////////////////////////
// DiskCacheAdapter
///////////////////////////////////////////////////////////////////////////////
class DiskCacheAdapter : public StreamAdapterInterface {
public:
DiskCacheAdapter(const DiskCache* cache, const std::string& id, size_t index,
StreamInterface* stream)
: StreamAdapterInterface(stream), cache_(cache), id_(id), index_(index)
{ }
virtual ~DiskCacheAdapter() {
Close();
cache_->ReleaseResource(id_, index_);
}
private:
const DiskCache* cache_;
std::string id_;
size_t index_;
};
///////////////////////////////////////////////////////////////////////////////
// DiskCache
///////////////////////////////////////////////////////////////////////////////
DiskCache::DiskCache() : max_cache_(0), total_size_(0), total_accessors_(0) {
}
DiskCache::~DiskCache() {
ASSERT(0 == total_accessors_);
}
bool DiskCache::Initialize(const std::string& folder, size_t size) {
if (!folder_.empty() || !Filesystem::CreateFolder(folder))
return false;
folder_ = folder;
max_cache_ = size;
ASSERT(0 == total_size_);
if (!InitializeEntries())
return false;
return CheckLimit();
}
bool DiskCache::Purge() {
if (folder_.empty())
return false;
if (total_accessors_ > 0) {
LOG_F(LS_WARNING) << "Cache files open";
return false;
}
if (!PurgeFiles())
return false;
map_.clear();
return true;
}
bool DiskCache::LockResource(const std::string& id) {
Entry* entry = GetOrCreateEntry(id, true);
if (LS_LOCKED == entry->lock_state)
return false;
if ((LS_UNLOCKED == entry->lock_state) && (entry->accessors > 0))
return false;
if ((total_size_ > max_cache_) && !CheckLimit()) {
LOG_F(LS_WARNING) << "Cache overfull";
return false;
}
entry->lock_state = LS_LOCKED;
return true;
}
StreamInterface* DiskCache::WriteResource(const std::string& id, size_t index) {
Entry* entry = GetOrCreateEntry(id, false);
if (LS_LOCKED != entry->lock_state)
return NULL;
size_t previous_size = 0;
std::string filename(IdToFilename(id, index));
FileStream::GetSize(filename, &previous_size);
ASSERT(previous_size <= entry->size);
if (previous_size > entry->size) {
previous_size = entry->size;
}
scoped_ptr<FileStream> file(new FileStream);
if (!file->Open(filename, "wb", NULL)) {
LOG_F(LS_ERROR) << "Couldn't create cache file";
return NULL;
}
entry->streams = stdmax(entry->streams, index + 1);
entry->size -= previous_size;
total_size_ -= previous_size;
entry->accessors += 1;
total_accessors_ += 1;
return new DiskCacheAdapter(this, id, index, file.release());
}
bool DiskCache::UnlockResource(const std::string& id) {
Entry* entry = GetOrCreateEntry(id, false);
if (LS_LOCKED != entry->lock_state)
return false;
if (entry->accessors > 0) {
entry->lock_state = LS_UNLOCKING;
} else {
entry->lock_state = LS_UNLOCKED;
entry->last_modified = time(0);
CheckLimit();
}
return true;
}
StreamInterface* DiskCache::ReadResource(const std::string& id,
size_t index) const {
const Entry* entry = GetEntry(id);
if (LS_UNLOCKED != entry->lock_state)
return NULL;
if (index >= entry->streams)
return NULL;
scoped_ptr<FileStream> file(new FileStream);
if (!file->Open(IdToFilename(id, index), "rb", NULL))
return NULL;
entry->accessors += 1;
total_accessors_ += 1;
return new DiskCacheAdapter(this, id, index, file.release());
}
bool DiskCache::HasResource(const std::string& id) const {
const Entry* entry = GetEntry(id);
return (NULL != entry) && (entry->streams > 0);
}
bool DiskCache::HasResourceStream(const std::string& id, size_t index) const {
const Entry* entry = GetEntry(id);
if ((NULL == entry) || (index >= entry->streams))
return false;
std::string filename = IdToFilename(id, index);
return FileExists(filename);
}
bool DiskCache::DeleteResource(const std::string& id) {
Entry* entry = GetOrCreateEntry(id, false);
if (!entry)
return true;
if ((LS_UNLOCKED != entry->lock_state) || (entry->accessors > 0))
return false;
bool success = true;
for (size_t index = 0; index < entry->streams; ++index) {
std::string filename = IdToFilename(id, index);
if (!FileExists(filename))
continue;
if (!DeleteFile(filename)) {
LOG_F(LS_ERROR) << "Couldn't remove cache file: " << filename;
success = false;
}
}
total_size_ -= entry->size;
map_.erase(id);
return success;
}
bool DiskCache::CheckLimit() {
#ifdef _DEBUG
// Temporary check to make sure everything is working correctly.
size_t cache_size = 0;
for (EntryMap::iterator it = map_.begin(); it != map_.end(); ++it) {
cache_size += it->second.size;
}
ASSERT(cache_size == total_size_);
#endif // _DEBUG
// TODO: Replace this with a non-brain-dead algorithm for clearing out the
// oldest resources... something that isn't O(n^2)
while (total_size_ > max_cache_) {
EntryMap::iterator oldest = map_.end();
for (EntryMap::iterator it = map_.begin(); it != map_.end(); ++it) {
if ((LS_UNLOCKED != it->second.lock_state) || (it->second.accessors > 0))
continue;
oldest = it;
break;
}
if (oldest == map_.end()) {
LOG_F(LS_WARNING) << "All resources are locked!";
return false;
}
for (EntryMap::iterator it = oldest++; it != map_.end(); ++it) {
if (it->second.last_modified < oldest->second.last_modified) {
oldest = it;
}
}
if (!DeleteResource(oldest->first)) {
LOG_F(LS_ERROR) << "Couldn't delete from cache!";
return false;
}
}
return true;
}
std::string DiskCache::IdToFilename(const std::string& id, size_t index) const {
#ifdef TRANSPARENT_CACHE_NAMES
// This escapes colons and other filesystem characters, so the user can't open
// special devices (like "COM1:"), or access other directories.
size_t buffer_size = id.length()*3 + 1;
char* buffer = new char[buffer_size];
encode(buffer, buffer_size, id.data(), id.length(),
unsafe_filename_characters(), '%');
// TODO: ASSERT(strlen(buffer) < FileSystem::MaxBasenameLength());
#else // !TRANSPARENT_CACHE_NAMES
// We might want to just use a hash of the filename at some point, both for
// obfuscation, and to avoid both filename length and escaping issues.
ASSERT(false);
#endif // !TRANSPARENT_CACHE_NAMES
char extension[32];
sprintfn(extension, ARRAY_SIZE(extension), ".%u", index);
Pathname pathname;
pathname.SetFolder(folder_);
pathname.SetBasename(buffer);
pathname.SetExtension(extension);
#ifdef TRANSPARENT_CACHE_NAMES
delete [] buffer;
#endif // TRANSPARENT_CACHE_NAMES
return pathname.pathname();
}
bool DiskCache::FilenameToId(const std::string& filename, std::string* id,
size_t* index) const {
Pathname pathname(filename);
unsigned tempdex;
if (1 != sscanf(pathname.extension().c_str(), ".%u", &tempdex))
return false;
*index = static_cast<size_t>(tempdex);
size_t buffer_size = pathname.basename().length() + 1;
char* buffer = new char[buffer_size];
decode(buffer, buffer_size, pathname.basename().data(),
pathname.basename().length(), '%');
id->assign(buffer);
delete [] buffer;
return true;
}
DiskCache::Entry* DiskCache::GetOrCreateEntry(const std::string& id,
bool create) {
EntryMap::iterator it = map_.find(id);
if (it != map_.end())
return &it->second;
if (!create)
return NULL;
Entry e;
e.lock_state = LS_UNLOCKED;
e.accessors = 0;
e.size = 0;
e.streams = 0;
e.last_modified = time(0);
it = map_.insert(EntryMap::value_type(id, e)).first;
return &it->second;
}
void DiskCache::ReleaseResource(const std::string& id, size_t index) const {
const Entry* entry = GetEntry(id);
if (!entry) {
LOG_F(LS_WARNING) << "Missing cache entry";
ASSERT(false);
return;
}
entry->accessors -= 1;
total_accessors_ -= 1;
if (LS_UNLOCKED != entry->lock_state) {
// This is safe, because locked resources only issue WriteResource, which
// is non-const. Think about a better way to handle it.
DiskCache* this2 = const_cast<DiskCache*>(this);
Entry* entry2 = this2->GetOrCreateEntry(id, false);
size_t new_size = 0;
std::string filename(IdToFilename(id, index));
FileStream::GetSize(filename, &new_size);
entry2->size += new_size;
this2->total_size_ += new_size;
if ((LS_UNLOCKING == entry->lock_state) && (0 == entry->accessors)) {
entry2->last_modified = time(0);
entry2->lock_state = LS_UNLOCKED;
this2->CheckLimit();
}
}
}
///////////////////////////////////////////////////////////////////////////////
} // namespace talk_base