diff options
Diffstat (limited to 'indra/llfilesystem/lldiskcache.h')
| -rw-r--r-- | indra/llfilesystem/lldiskcache.h | 146 |
1 files changed, 55 insertions, 91 deletions
diff --git a/indra/llfilesystem/lldiskcache.h b/indra/llfilesystem/lldiskcache.h index 39b8f7ef48..1618cec6a6 100644 --- a/indra/llfilesystem/lldiskcache.h +++ b/indra/llfilesystem/lldiskcache.h @@ -1,11 +1,6 @@ /** * @file lldiskcache.h - * @brief Declaration SQLite meta data / file storage API - * @brief Declaration of the generic disk cache interface - as well the SQLite header/implementation. - * @Note Eventually, this component might split into an interface - * file and multiple implemtations but for now, this is the - * only one so I think it's okay to combine everything. + * @brief The disk cache implementation. * * $LicenseInfo:firstyear=2009&license=viewerlgpl$ * Second Life Viewer Source Code @@ -32,99 +27,68 @@ #ifndef _LLDISKCACHE #define _LLDISKCACHE -#include <iostream> -#include <string> +class LLDiskCache +{ + public: + LLDiskCache(const std::string cache_dir); + ~LLDiskCache(); -#include "sqlite3.h" + /** + * Update the "last write time" of a file to "now". This must be called whenever a + * file in the cache is read (not written) so that the last time the file was + * accessed which is used in the mechanism for purging the cache, is up to date. + */ + void updateFileAccessTime(const std::string file_path); -// Enable this line to display each SQL statement when it is executed -// It can lead to a lot of spam but useful for debugging -//#define SHOW_STATEMENTS + /** + * Purge the oldest items in the cache so that the combined size of all files + * is no bigger than mMaxSizeBytes. + */ + void purge(); -// I toyed with the idea of a variety of approaches and thought have -// an abstract base class with which to hang different implementations -// off was a good idea but I think we settled on a single approach -// so I will likely remove this level of indirection if not other -// interesting implementation ideas present themselves. -class llDiskCacheBase -{ - public: - llDiskCacheBase() {}; - virtual ~llDiskCacheBase() {}; - virtual bool open(const std::string db_folder, - const std::string db_filename) = 0; - virtual bool exists(const std::string id, bool& exists) = 0; - virtual bool put(const std::string id, - char* binary_data, - int binary_data_size) = 0; - virtual const bool get(const std::string id, - char** mem_buffer, - int& mem_buffer_size) = 0; - virtual bool purge(int num_entries) = 0; - virtual void close() = 0; - virtual const std::string dbVersion() = 0; - virtual const std::string getFilenameById(const std::string id) = 0; - virtual const int getAccessCountById(const std::string id) = 0; - virtual void getNumEntries(int& num_entries, int& max_entries) = 0; -}; + /** + * Clear the cache by removing the files in the cache directory individually + */ + void clearCache(const std::string cache_dir); -// implementation for the SQLite/disk blended case -// see source file for detailed comments -class llDiskCache : - public llDiskCacheBase -{ - public: - llDiskCache(); - virtual ~llDiskCache(); - virtual bool open(const std::string db_folder, - const std::string db_filename) override; - virtual bool exists(const std::string id, bool& exists) override; - virtual bool put(const std::string id, - char* binary_data, - int binary_data_size) override; - virtual const bool get(const std::string id, - char** mem_buffer, - int& mem_buffer_size) override; - virtual bool purge(int num_entries) override; - virtual void close() override; - virtual const std::string dbVersion() override; - virtual const std::string getFilenameById(const std::string id) override; - virtual const int getAccessCountById(const std::string id) override; - virtual void getNumEntries(int& num_entries, int& max_entries) override; + /** + * Manage max size in bytes of cache - use a discrete setter/getter so the value can + * be changed in the preferences and cache cleared/purged without restarting viewer + * to instantiate this class again. + */ + void setMaxSizeBytes(const uintmax_t size_bytes) { mMaxSizeBytes = size_bytes; } + uintmax_t getMaxSizeBytes() const { return mMaxSizeBytes; } private: - sqlite3* mDb; - std::string mDataStorePath; - const std::string mTableName = "lldiskcache"; - const std::string mIdFieldName = "id"; - const std::string mFilenameFieldName = "filename"; - const std::string mFilesizeFieldName = "filesize"; - const std::string mInsertionDateTimeFieldName = "insert_datetime"; - const std::string mLastAccessDateTimeFieldName = "last_access_datetime"; - const std::string mAccessCountFieldName = "access_count"; + /** + * Utility function to gather the total size the files in a given + * directory. Primarily used here to determine the directory size + * before and after the cache purge + */ + uintmax_t dirFileSize(const std::string dir); private: - void printError(const std::string funcname, - const std::string desc, - bool is_sqlite_err); - bool beginTransaction(); - bool endTransaction(); - std::string makeUniqueFilename(); - const std::string systemSeparator(); - const std::string makeFullPath(const std::string filename); - bool sqliteExec(const std::string stmt, - const std::string funcname); - sqlite3_stmt* sqlitePrepareStep(const std::string funcname, - const std::string stmt, - int sqlite_success_condition); - const std::string sqlComposeCreateTable(); - const std::string sqlComposeExists(const std::string id); - const std::string sqlComposePut(const std::string id, - const std::string filename, - int binary_data_size); - const std::string sqlComposeGetSelect(const std::string id); - const std::string sqlComposeGetUpdate(const std::string id); - const std::string sqlComposePurge(int num_entries); + /** + * Default of 20MB seems reasonable - it will likely be reset + * immediately anyway using a value from the Viewer settings + */ + const uintmax_t mDefaultSizeBytes = 20 * 1024 * 1024; + uintmax_t mMaxSizeBytes; + + /** + * The folder that holds the cached files. The consumer of this + * class must avoid letting the user set this location as a malicious + * setting could potentially point it at a non-cache directory (for example, + * the Windows System dir) with disastrous results. + */ + std::string mCacheDir; + + /** + * This is set from the CacheDebugInfo global setting and + * when enabled, displays additional debugging information in + * various parts of the code + */ + bool mCacheDebugInfo; }; #endif // _LLDISKCACHE |