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Diffstat (limited to 'Plugins/jingle/libjingle/talk/base/diskcache.cc')
-rw-r--r-- | Plugins/jingle/libjingle/talk/base/diskcache.cc | 362 |
1 files changed, 362 insertions, 0 deletions
diff --git a/Plugins/jingle/libjingle/talk/base/diskcache.cc b/Plugins/jingle/libjingle/talk/base/diskcache.cc new file mode 100644 index 0000000..44e37d9 --- /dev/null +++ b/Plugins/jingle/libjingle/talk/base/diskcache.cc @@ -0,0 +1,362 @@ +/* + * 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/basicdefs.h" +#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")) { + 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")) + 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); + if (1 != sscanf(pathname.extension().c_str(), ".%u", index)) + return false; + + 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 |