77// See http://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
88//
99
10+ import SQLite3
1011
1112/*!
1213 @enum URLCache.StoragePolicy
@@ -123,6 +124,26 @@ open class CachedURLResponse : NSObject, NSSecureCoding, NSCopying {
123124
124125open class URLCache : NSObject {
125126
127+ private static let sharedSyncQ = DispatchQueue ( label: " org.swift.URLCache.sharedSyncQ " )
128+
129+ private static var sharedCache : URLCache ? {
130+ willSet {
131+ URLCache . sharedCache? . syncQ. sync {
132+ URLCache . sharedCache? . _databaseClient? . close ( )
133+ URLCache . sharedCache? . flushDatabase ( )
134+ }
135+ }
136+ didSet {
137+ URLCache . sharedCache? . syncQ. sync {
138+ URLCache . sharedCache? . setupCacheDatabaseIfNotExist ( )
139+ }
140+ }
141+ }
142+
143+ private let syncQ = DispatchQueue ( label: " org.swift.URLCache.syncQ " )
144+ private let _baseDiskPath : String ?
145+ private var _databaseClient : _CacheSQLiteClient ?
146+
126147 /*!
127148 @method sharedURLCache
128149 @abstract Returns the shared URLCache instance.
@@ -142,10 +163,22 @@ open class URLCache : NSObject {
142163 */
143164 open class var shared : URLCache {
144165 get {
145- NSUnimplemented ( )
166+ return sharedSyncQ. sync {
167+ if let cache = sharedCache {
168+ return cache
169+ } else {
170+ let fourMegaByte = 4 * 1024 * 1024
171+ let twentyMegaByte = 20 * 1024 * 1024
172+ let cacheDirectoryPath = FileManager . default. urls ( for: . cachesDirectory, in: . userDomainMask) . first? . path ?? " \( NSHomeDirectory ( ) ) /Library/Caches/ "
173+ let path = " \( cacheDirectoryPath) \( Bundle . main. bundleIdentifier ?? UUID ( ) . uuidString) "
174+ let cache = URLCache ( memoryCapacity: fourMegaByte, diskCapacity: twentyMegaByte, diskPath: path)
175+ sharedCache = cache
176+ return cache
177+ }
178+ }
146179 }
147180 set {
148- NSUnimplemented ( )
181+ sharedSyncQ . sync { sharedCache = newValue }
149182 }
150183 }
151184
@@ -162,7 +195,13 @@ open class URLCache : NSObject {
162195 @result an initialized URLCache, with the given capacity, backed
163196 by disk.
164197 */
165- public init ( memoryCapacity: Int , diskCapacity: Int , diskPath path: String ? ) { NSUnimplemented ( ) }
198+ public init ( memoryCapacity: Int , diskCapacity: Int , diskPath path: String ? ) {
199+ self . memoryCapacity = memoryCapacity
200+ self . diskCapacity = diskCapacity
201+ self . _baseDiskPath = path
202+
203+ super. init ( )
204+ }
166205
167206 /*!
168207 @method cachedResponseForRequest:
@@ -244,10 +283,132 @@ open class URLCache : NSObject {
244283 @result the current usage of the on-disk cache of the receiver.
245284 */
246285 open var currentDiskUsage : Int { NSUnimplemented ( ) }
286+
287+ private func flushDatabase( ) {
288+ guard let path = _baseDiskPath else { return }
289+
290+ do {
291+ let dbPath = path. appending ( " /Cache.db " )
292+ try FileManager . default. removeItem ( atPath: dbPath)
293+ } catch {
294+ fatalError ( " Unable to flush database for URLCache: \( error. localizedDescription) " )
295+ }
296+ }
297+
247298}
248299
249300extension URLCache {
250301 public func storeCachedResponse( _ cachedResponse: CachedURLResponse , for dataTask: URLSessionDataTask ) { NSUnimplemented ( ) }
251302 public func getCachedResponse( for dataTask: URLSessionDataTask , completionHandler: ( CachedURLResponse ? ) -> Void ) { NSUnimplemented ( ) }
252303 public func removeCachedResponse( for dataTask: URLSessionDataTask ) { NSUnimplemented ( ) }
253304}
305+
306+ extension URLCache {
307+
308+ private func setupCacheDatabaseIfNotExist( ) {
309+ guard let path = _baseDiskPath else { return }
310+
311+ if !FileManager. default. fileExists ( atPath: path) {
312+ do {
313+ try FileManager . default. createDirectory ( atPath: path, withIntermediateDirectories: true )
314+ } catch {
315+ fatalError ( " Unable to create directories for URLCache: \( error. localizedDescription) " )
316+ }
317+ }
318+
319+ // Close the currently opened database connection(if any), before creating/replacing the db file
320+ _databaseClient? . close ( )
321+
322+ let dbPath = path. appending ( " /Cache.db " )
323+ if !FileManager. default. createFile ( atPath: dbPath, contents: nil , attributes: nil ) {
324+ fatalError ( " Unable to setup database for URLCache " )
325+ }
326+
327+ _databaseClient = _CacheSQLiteClient ( databasePath: dbPath)
328+ if _databaseClient == nil {
329+ _databaseClient? . close ( )
330+ flushDatabase ( )
331+ fatalError ( " Unable to setup database for URLCache " )
332+ }
333+
334+ if !createTables( ) {
335+ _databaseClient? . close ( )
336+ flushDatabase ( )
337+ fatalError ( " Unable to setup database for URLCache: Tables not created " )
338+ }
339+
340+ if !createIndicesForTables( ) {
341+ _databaseClient? . close ( )
342+ flushDatabase ( )
343+ fatalError ( " Unable to setup database for URLCache: Indices not created for tables " )
344+ }
345+ }
346+
347+ private func createTables( ) -> Bool {
348+ guard _databaseClient != nil else {
349+ fatalError ( " Cannot create table before database setup " )
350+ }
351+
352+ let tableSQLs = [
353+ " CREATE TABLE cfurl_cache_response(entry_ID INTEGER PRIMARY KEY, version INTEGER, hash_value VARCHAR, storage_policy INTEGER, request_key VARCHAR, time_stamp DATETIME, partition VARCHAR) " ,
354+ " CREATE TABLE cfurl_cache_receiver_data(entry_ID INTEGER PRIMARY KEY, isDataOnFS INTEGER, receiver_data BLOB) " ,
355+ " CREATE TABLE cfurl_cache_blob_data(entry_ID INTEGER PRIMARY KEY, response_object BLOB, request_object BLOB, proto_props BLOB, user_info BLOB) " ,
356+ " CREATE TABLE cfurl_cache_schema_version(schema_version INTEGER) "
357+ ]
358+
359+ for sql in tableSQLs {
360+ if let isSuccess = _databaseClient? . execute ( sql: sql) , !isSuccess {
361+ return false
362+ }
363+ }
364+
365+ return true
366+ }
367+
368+ private func createIndicesForTables( ) -> Bool {
369+ guard _databaseClient != nil else {
370+ fatalError ( " Cannot create table before database setup " )
371+ }
372+
373+ let indicesSQLs = [
374+ " CREATE INDEX proto_props_index ON cfurl_cache_blob_data(entry_ID) " ,
375+ " CREATE INDEX receiver_data_index ON cfurl_cache_receiver_data(entry_ID) " ,
376+ " CREATE INDEX request_key_index ON cfurl_cache_response(request_key) " ,
377+ " CREATE INDEX time_stamp_index ON cfurl_cache_response(time_stamp) "
378+ ]
379+
380+ for sql in indicesSQLs {
381+ if let isSuccess = _databaseClient? . execute ( sql: sql) , !isSuccess {
382+ return false
383+ }
384+ }
385+
386+ return true
387+ }
388+
389+ }
390+
391+ fileprivate struct _CacheSQLiteClient {
392+
393+ private var database : OpaquePointer ?
394+
395+ init ? ( databasePath: String ) {
396+ if sqlite3_open_v2 ( databasePath, & database, SQLITE_OPEN_CREATE | SQLITE_OPEN_READWRITE, nil ) != SQLITE_OK {
397+ return nil
398+ }
399+ }
400+
401+ func execute( sql: String ) -> Bool {
402+ guard let db = database else { return false }
403+
404+ return sqlite3_exec ( db, sql, nil , nil , nil ) == SQLITE_OK
405+ }
406+
407+ mutating func close( ) {
408+ guard let db = database else { return }
409+
410+ sqlite3_close_v2 ( db)
411+ database = nil
412+ }
413+
414+ }
0 commit comments