461 lines
17 KiB
C++
461 lines
17 KiB
C++
/**
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* @file lldiskcache.cpp
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* @brief The disk cache implementation.
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*
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* Note: Rather than keep the top level function comments up
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* to date in both the source and header files, I elected to
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* only have explicit comments about each function and variable
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* in the header - look there for details. The same is true for
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* description of how this code is supposed to work.
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*
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* $LicenseInfo:firstyear=2009&license=viewerlgpl$
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* Second Life Viewer Source Code
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* Copyright (C) 2020, Linden Research, Inc.
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation;
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* version 2.1 of the License only.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*
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* Linden Research, Inc., 945 Battery Street, San Francisco, CA 94111 USA
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* $/LicenseInfo$
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*/
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#include "linden_common.h"
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#include "llapp.h"
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#include "llassettype.h"
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#include "lldir.h"
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#include <boost/filesystem.hpp>
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#include <chrono>
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#include "lldiskcache.h"
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LLDiskCache::LLDiskCache(const std::string cache_dir,
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const uintmax_t max_size_bytes,
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const bool enable_cache_debug_info) :
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mCacheDir(cache_dir),
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mMaxSizeBytes(max_size_bytes),
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mEnableCacheDebugInfo(enable_cache_debug_info)
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{
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mCacheFilenamePrefix = "sl_cache";
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LLFile::mkdir(cache_dir);
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}
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// WARNING: purge() is called by LLPurgeDiskCacheThread. As such it must
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// NOT touch any LLDiskCache data without introducing and locking a mutex!
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// Interaction through the filesystem itself should be safe. Let’s say thread
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// A is accessing the cache file for reading/writing and thread B is trimming
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// the cache. Let’s also assume using llifstream to open a file and
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// boost::filesystem::remove are not atomic (which will be pretty much the
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// case).
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// Now, A is trying to open the file using llifstream ctor. It does some
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// checks if the file exists and whatever else it might be doing, but has not
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// issued the call to the OS to actually open the file yet. Now B tries to
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// delete the file: If the file has been already marked as in use by the OS,
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// deleting the file will fail and B will continue with the next file. A can
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// safely continue opening the file. If the file has not yet been marked as in
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// use, B will delete the file. Now A actually wants to open it, operation
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// will fail, subsequent check via llifstream.is_open will fail, asset will
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// have to be re-requested. (Assuming here the viewer will actually handle
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// this situation properly, that can also happen if there is a file containing
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// garbage.)
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// Other situation: B is trimming the cache and A wants to read a file that is
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// about to get deleted. boost::filesystem::remove does whatever it is doing
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// before actually deleting the file. If A opens the file before the file is
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// actually gone, the OS call from B to delete the file will fail since the OS
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// will prevent this. B continues with the next file. If the file is already
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// gone before A finally gets to open it, this operation will fail and the
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// asset will have to be re-requested.
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void LLDiskCache::purge()
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{
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if (mEnableCacheDebugInfo)
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{
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LL_INFOS() << "Total dir size before purge is " << dirFileSize(mCacheDir) << LL_ENDL;
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}
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boost::system::error_code ec;
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auto start_time = std::chrono::high_resolution_clock::now();
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typedef std::pair<std::time_t, std::pair<uintmax_t, std::string>> file_info_t;
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std::vector<file_info_t> file_info;
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#if LL_WINDOWS
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std::wstring cache_path(utf8str_to_utf16str(mCacheDir));
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#else
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std::string cache_path(mCacheDir);
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#endif
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if (boost::filesystem::is_directory(cache_path, ec) && !ec.failed())
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{
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boost::filesystem::directory_iterator iter(cache_path, ec);
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while (iter != boost::filesystem::directory_iterator() && !ec.failed())
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{
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if (boost::filesystem::is_regular_file(*iter, ec) && !ec.failed())
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{
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if ((*iter).path().string().find(mCacheFilenamePrefix) != std::string::npos)
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{
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uintmax_t file_size = boost::filesystem::file_size(*iter, ec);
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if (ec.failed())
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{
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continue;
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}
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const std::string file_path = (*iter).path().string();
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const std::time_t file_time = boost::filesystem::last_write_time(*iter, ec);
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if (ec.failed())
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{
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continue;
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}
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file_info.push_back(file_info_t(file_time, { file_size, file_path }));
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}
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}
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iter.increment(ec);
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}
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}
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std::sort(file_info.begin(), file_info.end(), [](file_info_t& x, file_info_t& y)
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{
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return x.first > y.first;
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});
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LL_INFOS() << "Purging cache to a maximum of " << mMaxSizeBytes << " bytes" << LL_ENDL;
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std::vector<bool> file_removed;
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if (mEnableCacheDebugInfo)
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{
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file_removed.reserve(file_info.size());
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}
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uintmax_t file_size_total = 0;
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for (file_info_t& entry : file_info)
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{
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file_size_total += entry.second.first;
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bool should_remove = file_size_total > mMaxSizeBytes;
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if (mEnableCacheDebugInfo)
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{
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file_removed.push_back(should_remove);
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}
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if (should_remove)
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{
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boost::filesystem::remove(entry.second.second, ec);
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if (ec.failed())
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{
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LL_WARNS() << "Failed to delete cache file " << entry.second.second << ": " << ec.message() << LL_ENDL;
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}
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}
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}
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if (mEnableCacheDebugInfo)
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{
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auto end_time = std::chrono::high_resolution_clock::now();
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auto execute_time = std::chrono::duration_cast<std::chrono::milliseconds>(end_time - start_time).count();
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// Log afterward so it doesn't affect the time measurement
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// Logging thousands of file results can take hundreds of milliseconds
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for (size_t i = 0; i < file_info.size(); ++i)
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{
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const file_info_t& entry = file_info[i];
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const bool removed = file_removed[i];
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const std::string action = removed ? "DELETE:" : "KEEP:";
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// have to do this because of LL_INFO/LL_END weirdness
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std::ostringstream line;
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line << action << " ";
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line << entry.first << " ";
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line << entry.second.first << " ";
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line << entry.second.second;
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line << " (" << file_size_total << "/" << mMaxSizeBytes << ")";
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LL_INFOS() << line.str() << LL_ENDL;
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}
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LL_INFOS() << "Total dir size after purge is " << dirFileSize(mCacheDir) << LL_ENDL;
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LL_INFOS() << "Cache purge took " << execute_time << " ms to execute for " << file_info.size() << " files" << LL_ENDL;
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}
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}
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const std::string LLDiskCache::assetTypeToString(LLAssetType::EType at)
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{
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/**
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* Make use of the handy C++17 feature that allows
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* for inline initialization of an std::map<>
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*/
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typedef std::map<LLAssetType::EType, std::string> asset_type_to_name_t;
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asset_type_to_name_t asset_type_to_name =
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{
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{ LLAssetType::AT_TEXTURE, "TEXTURE" },
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{ LLAssetType::AT_SOUND, "SOUND" },
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{ LLAssetType::AT_CALLINGCARD, "CALLINGCARD" },
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{ LLAssetType::AT_LANDMARK, "LANDMARK" },
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{ LLAssetType::AT_SCRIPT, "SCRIPT" },
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{ LLAssetType::AT_CLOTHING, "CLOTHING" },
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{ LLAssetType::AT_OBJECT, "OBJECT" },
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{ LLAssetType::AT_NOTECARD, "NOTECARD" },
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{ LLAssetType::AT_CATEGORY, "CATEGORY" },
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{ LLAssetType::AT_LSL_TEXT, "LSL_TEXT" },
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{ LLAssetType::AT_LSL_BYTECODE, "LSL_BYTECODE" },
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{ LLAssetType::AT_TEXTURE_TGA, "TEXTURE_TGA" },
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{ LLAssetType::AT_BODYPART, "BODYPART" },
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{ LLAssetType::AT_SOUND_WAV, "SOUND_WAV" },
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{ LLAssetType::AT_IMAGE_TGA, "IMAGE_TGA" },
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{ LLAssetType::AT_IMAGE_JPEG, "IMAGE_JPEG" },
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{ LLAssetType::AT_ANIMATION, "ANIMATION" },
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{ LLAssetType::AT_GESTURE, "GESTURE" },
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{ LLAssetType::AT_SIMSTATE, "SIMSTATE" },
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{ LLAssetType::AT_LINK, "LINK" },
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{ LLAssetType::AT_LINK_FOLDER, "LINK_FOLDER" },
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{ LLAssetType::AT_MARKETPLACE_FOLDER, "MARKETPLACE_FOLDER" },
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{ LLAssetType::AT_WIDGET, "WIDGET" },
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{ LLAssetType::AT_PERSON, "PERSON" },
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{ LLAssetType::AT_MESH, "MESH" },
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{ LLAssetType::AT_SETTINGS, "SETTINGS" },
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{ LLAssetType::AT_UNKNOWN, "UNKNOWN" }
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};
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asset_type_to_name_t::iterator iter = asset_type_to_name.find(at);
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if (iter != asset_type_to_name.end())
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{
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return iter->second;
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}
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return std::string("UNKNOWN");
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}
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const std::string LLDiskCache::metaDataToFilepath(const std::string id,
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LLAssetType::EType at,
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const std::string extra_info)
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{
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std::ostringstream file_path;
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file_path << mCacheDir;
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file_path << gDirUtilp->getDirDelimiter();
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file_path << mCacheFilenamePrefix;
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file_path << "_";
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file_path << id;
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file_path << "_";
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file_path << (extra_info.empty() ? "0" : extra_info);
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//file_path << "_";
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//file_path << assetTypeToString(at); // see SL-14210 Prune descriptive tag from new cache filenames
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// for details of why it was removed. Note that if you put it
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// back or change the format of the filename, the cache files
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// files will be invalidated (and perhaps, more importantly,
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// never deleted unless you delete them manually).
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file_path << ".asset";
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return file_path.str();
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}
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void LLDiskCache::updateFileAccessTime(const std::string file_path)
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{
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/**
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* Threshold in time_t units that is used to decide if the last access time
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* time of the file is updated or not. Added as a precaution for the concern
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* outlined in SL-14582 about frequent writes on older SSDs reducing their
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* lifespan. I think this is the right place for the threshold value - rather
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* than it being a pref - do comment on that Jira if you disagree...
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*
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* Let's start with 1 hour in time_t units and see how that unfolds
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*/
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const std::time_t time_threshold = 1 * 60 * 60;
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// current time
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const std::time_t cur_time = std::time(nullptr);
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boost::system::error_code ec;
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#if LL_WINDOWS
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// file last write time
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const std::time_t last_write_time = boost::filesystem::last_write_time(utf8str_to_utf16str(file_path), ec);
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if (ec.failed())
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{
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LL_WARNS() << "Failed to read last write time for cache file " << file_path << ": " << ec.message() << LL_ENDL;
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return;
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}
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// delta between cur time and last time the file was written
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const std::time_t delta_time = cur_time - last_write_time;
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// we only write the new value if the time in time_threshold has elapsed
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// before the last one
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if (delta_time > time_threshold)
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{
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boost::filesystem::last_write_time(utf8str_to_utf16str(file_path), cur_time, ec);
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}
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#else
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// file last write time
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const std::time_t last_write_time = boost::filesystem::last_write_time(file_path, ec);
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if (ec.failed())
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{
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LL_WARNS() << "Failed to read last write time for cache file " << file_path << ": " << ec.message() << LL_ENDL;
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return;
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}
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// delta between cur time and last time the file was written
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const std::time_t delta_time = cur_time - last_write_time;
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// we only write the new value if the time in time_threshold has elapsed
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// before the last one
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if (delta_time > time_threshold)
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{
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boost::filesystem::last_write_time(file_path, cur_time, ec);
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}
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#endif
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if (ec.failed())
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{
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LL_WARNS() << "Failed to update last write time for cache file " << file_path << ": " << ec.message() << LL_ENDL;
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}
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}
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const std::string LLDiskCache::getCacheInfo()
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{
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std::ostringstream cache_info;
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F32 max_in_mb = (F32)mMaxSizeBytes / (1024.0 * 1024.0);
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F32 percent_used = ((F32)dirFileSize(mCacheDir) / (F32)mMaxSizeBytes) * 100.0;
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cache_info << std::fixed;
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cache_info << std::setprecision(1);
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cache_info << "Max size " << max_in_mb << " MB ";
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cache_info << "(" << percent_used << "% used)";
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return cache_info.str();
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}
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void LLDiskCache::clearCache()
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{
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/**
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* See notes on performance in dirFileSize(..) - there may be
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* a quicker way to do this by operating on the parent dir vs
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* the component files but it's called infrequently so it's
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* likely just fine
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*/
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boost::system::error_code ec;
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#if LL_WINDOWS
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std::wstring cache_path(utf8str_to_utf16str(mCacheDir));
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#else
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std::string cache_path(mCacheDir);
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#endif
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if (boost::filesystem::is_directory(cache_path, ec) && !ec.failed())
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{
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boost::filesystem::directory_iterator iter(cache_path, ec);
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while (iter != boost::filesystem::directory_iterator() && !ec.failed())
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{
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if (boost::filesystem::is_regular_file(*iter, ec) && !ec.failed())
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{
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if ((*iter).path().string().find(mCacheFilenamePrefix) != std::string::npos)
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{
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boost::filesystem::remove(*iter, ec);
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if (ec.failed())
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{
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LL_WARNS() << "Failed to delete cache file " << *iter << ": " << ec.message() << LL_ENDL;
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}
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}
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}
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iter.increment(ec);
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}
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}
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}
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void LLDiskCache::removeOldVFSFiles()
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{
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//VFS files won't be created, so consider removing this code later
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static const char CACHE_FORMAT[] = "inv.llsd";
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static const char DB_FORMAT[] = "db2.x";
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boost::system::error_code ec;
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#if LL_WINDOWS
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std::wstring cache_path(utf8str_to_utf16str(gDirUtilp->getExpandedFilename(LL_PATH_CACHE, "")));
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#else
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std::string cache_path(gDirUtilp->getExpandedFilename(LL_PATH_CACHE, ""));
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#endif
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if (boost::filesystem::is_directory(cache_path, ec) && !ec.failed())
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{
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boost::filesystem::directory_iterator iter(cache_path, ec);
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while (iter != boost::filesystem::directory_iterator() && !ec.failed())
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{
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if (boost::filesystem::is_regular_file(*iter, ec) && !ec.failed())
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{
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if (((*iter).path().string().find(CACHE_FORMAT) != std::string::npos) ||
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((*iter).path().string().find(DB_FORMAT) != std::string::npos))
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{
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boost::filesystem::remove(*iter, ec);
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if (ec.failed())
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{
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LL_WARNS() << "Failed to delete cache file " << *iter << ": " << ec.message() << LL_ENDL;
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}
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}
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}
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iter.increment(ec);
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}
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}
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}
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uintmax_t LLDiskCache::dirFileSize(const std::string dir)
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{
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uintmax_t total_file_size = 0;
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/**
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* There may be a better way that works directly on the folder (similar to
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* right clicking on a folder in the OS and asking for size vs right clicking
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* on all files and adding up manually) but this is very fast - less than 100ms
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* for 10,000 files in my testing so, so long as it's not called frequently,
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* it should be okay. Note that's it's only currently used for logging/debugging
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* so if performance is ever an issue, optimizing this or removing it altogether,
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* is an easy win.
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*/
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boost::system::error_code ec;
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#if LL_WINDOWS
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std::wstring dir_path(utf8str_to_utf16str(dir));
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#else
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std::string dir_path(dir);
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#endif
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if (boost::filesystem::is_directory(dir_path, ec) && !ec.failed())
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{
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boost::filesystem::directory_iterator iter(dir_path, ec);
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while (iter != boost::filesystem::directory_iterator() && !ec.failed())
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{
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if (boost::filesystem::is_regular_file(*iter, ec) && !ec.failed())
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{
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if ((*iter).path().string().find(mCacheFilenamePrefix) != std::string::npos)
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{
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uintmax_t file_size = boost::filesystem::file_size(*iter, ec);
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if (!ec.failed())
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{
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total_file_size += file_size;
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}
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}
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}
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iter.increment(ec);
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}
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}
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return total_file_size;
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}
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LLPurgeDiskCacheThread::LLPurgeDiskCacheThread() :
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LLThread("PurgeDiskCacheThread", nullptr)
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{
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}
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void LLPurgeDiskCacheThread::run()
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{
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constexpr std::chrono::seconds CHECK_INTERVAL{60};
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while (LLApp::instance()->sleep(CHECK_INTERVAL))
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{
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LLDiskCache::instance().purge();
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}
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}
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