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+//
+// $Id$
+//
+// SPDatabaseStructure.m
+// sequel-pro
+//
+// Created by Hans-Jörg Bibiko on March 25, 2010
+// Copyright (c) 2010 Hans-Jörg Bibiko. All rights reserved.
+//
+// This program is free software; you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation; either version 2 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program; if not, write to the Free Software
+// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+//
+// More info at <http://code.google.com/p/sequel-pro/>
+
+#import "SPDatabaseStructure.h"
+#import "SPDatabaseDocument.h"
+#import "SPConnectionDelegate.h"
+#import "SPTablesList.h"
+#import "RegexKitLite.h"
+#import "SPMySQL.h"
+#import <pthread.h>
+
+@interface SPDatabaseStructure (Private_API)
+
+- (void)_updateGlobalVariablesWithStructure:(NSDictionary *)aStructure keys:(NSArray *)theKeys;
+- (void)_cloneConnectionFromConnection:(SPMySQLConnection *)aConnection;
+- (BOOL)_ensureConnection;
+
+@end
+
+#pragma mark -
+
+@implementation SPDatabaseStructure
+
+#pragma mark -
+#pragma mark Setup and teardown
+
+/**
+ * Prevent SPDatabaseStructure from being init'd normally.
+ */
+- (id)init
+{
+ [NSException raise:NSInternalInconsistencyException format:@"SPDatabaseStructures should not be init'd directly; use initWithDelegate: instead."];
+ return nil;
+}
+
+/**
+ * Standard init method, constructing the SPDatabaseStructure around a SPMySQL
+ * connection pointer and a delegate.
+ */
+- (id)initWithDelegate:(SPDatabaseDocument *)theDelegate
+{
+ if ((self = [super init])) {
+
+ // Keep a weak reference to the delegate
+ delegate = theDelegate;
+
+ // Start with no root connection
+ mySQLConnection = nil;
+
+ // Set up empty structure and keys storage
+ structureRetrievalThreads = [[NSMutableArray alloc] init];
+ structure = [[NSMutableDictionary alloc] initWithCapacity:1];
+ allKeysofDbStructure = [[NSMutableArray alloc] initWithCapacity:20];
+
+ // Set up the connection, thread management and data locks
+ pthread_mutex_init(&threadManagementLock, NULL);
+ pthread_mutex_init(&dataLock, NULL);
+ pthread_mutex_init(&connectionCheckLock, NULL);
+ }
+
+ return self;
+}
+
+/**
+ * Rather than supplying a connection to SPDatabaseStructure, the class instead
+ * will set up its own connection to allow background querying. The supplied
+ * connection will be used to look up details for the clone process.
+ */
+- (void)setConnectionToClone:(SPMySQLConnection *)aConnection
+{
+
+ // Perform the task in a background thread to avoid blocking the UI
+ [NSThread detachNewThreadSelector:@selector(_cloneConnectionFromConnection:) toTarget:self withObject:aConnection];
+}
+
+- (void)dealloc
+{
+
+ // Ensure all the retrieval threads have ended
+ pthread_mutex_lock(&threadManagementLock);
+ if ([structureRetrievalThreads count]) {
+ for (NSThread *eachThread in structureRetrievalThreads) {
+ [eachThread cancel];
+ }
+ while ([structureRetrievalThreads count]) {
+ pthread_mutex_unlock(&threadManagementLock);
+ usleep(100000);
+ pthread_mutex_lock(&threadManagementLock);
+ }
+ }
+ pthread_mutex_unlock(&threadManagementLock);
+ [structureRetrievalThreads release];
+
+ pthread_mutex_destroy(&threadManagementLock);
+ pthread_mutex_destroy(&dataLock);
+ pthread_mutex_destroy(&connectionCheckLock);
+ delegate = nil;
+
+ if (mySQLConnection) [mySQLConnection release], mySQLConnection = nil;
+ if (structure) [structure release], structure = nil;
+ if (allKeysofDbStructure) [allKeysofDbStructure release], allKeysofDbStructure = nil;
+
+ [super dealloc];
+}
+
+#pragma mark -
+#pragma mark Information
+
+- (SPMySQLConnection *)connection
+{
+ return mySQLConnection;
+}
+
+#pragma mark -
+#pragma mark Structure retrieval from the server
+
+/**
+ * Updates the dict containing the structure of all available databases (mainly for completion/navigator)
+ * executed on the helper connection.
+ * Should always be executed on a background thread.
+ */
+- (void)queryDbStructureWithUserInfo:(NSDictionary*)userInfo
+{
+ NSAutoreleasePool *queryPool = [[NSAutoreleasePool alloc] init];
+ BOOL structureWasUpdated = NO;
+
+ // Lock the management lock
+ pthread_mutex_lock(&threadManagementLock);
+
+ // If 'cancelQuerying' is set try to interrupt any current querying
+ if (userInfo && [userInfo objectForKey:@"cancelQuerying"]) {
+ for (NSThread *eachThread in structureRetrievalThreads) {
+ [eachThread cancel];
+ }
+ }
+
+ // Add this thread to the group
+ [structureRetrievalThreads addObject:[NSThread currentThread]];
+
+ // Only allow one request to be running against the server at any one time, to prevent
+ // escessive server i/o or slowdown. Loop until this is the first thread in the array
+ while ([structureRetrievalThreads objectAtIndex:0] != [NSThread currentThread]) {
+ if ([[NSThread currentThread] isCancelled]) {
+ [structureRetrievalThreads removeObject:[NSThread currentThread]];
+ pthread_mutex_unlock(&threadManagementLock);
+ [queryPool release];
+ return;
+ }
+
+ pthread_mutex_unlock(&threadManagementLock);
+ usleep(1000000);
+ pthread_mutex_lock(&threadManagementLock);
+ }
+ pthread_mutex_unlock(&threadManagementLock);
+
+ // This thread is now first on the stack, and about to process the structure.
+ [[NSNotificationCenter defaultCenter] postNotificationName:@"SPDBStructureIsUpdating" object:delegate];
+
+ NSString *connectionID;
+ if([delegate respondsToSelector:@selector(connectionID)])
+ connectionID = [NSString stringWithString:[delegate connectionID]];
+ else
+ connectionID = @"_";
+
+ // Re-init with already cached data from navigator controller
+ NSMutableDictionary *queriedStructure = [NSMutableDictionary dictionary];
+ NSDictionary *dbstructure = [delegate getDbStructure];
+ if (dbstructure) [queriedStructure setDictionary:[NSMutableDictionary dictionaryWithDictionary:dbstructure]];
+
+ NSMutableArray *queriedStructureKeys = [NSMutableArray array];
+ NSArray *dbStructureKeys = [delegate allSchemaKeys];
+ if (dbStructureKeys) [queriedStructureKeys setArray:dbStructureKeys];
+
+ // Retrieve all the databases known of by the delegate
+ NSMutableArray *connectionDatabases = [NSMutableArray array];
+ [connectionDatabases addObjectsFromArray:[delegate allSystemDatabaseNames]];
+ [connectionDatabases addObjectsFromArray:[delegate allDatabaseNames]];
+
+ // Add all known databases coming from connection if they aren't parsed yet
+ for (id db in connectionDatabases) {
+ NSString *dbid = [NSString stringWithFormat:@"%@%@%@", connectionID, SPUniqueSchemaDelimiter, db];
+ if(![queriedStructure objectForKey:dbid]) {
+ structureWasUpdated = YES;
+ [queriedStructure setObject:db forKey:dbid];
+ [queriedStructureKeys addObject:dbid];
+ }
+ }
+
+ // Check the existing databases in the 'structure' and 'allKeysOfDbStructure' stores,
+ // and remove any that are no longer found in the connectionDatabases list (indicating deletion).
+ // Iterate through extracted keys to avoid <NSCFDictionary> mutation while being enumerated.
+ NSArray *keys = [queriedStructure allKeys];
+ for(id key in keys) {
+ NSString *db = [[key componentsSeparatedByString:SPUniqueSchemaDelimiter] objectAtIndex:1];
+ if(![connectionDatabases containsObject:db]) {
+ structureWasUpdated = YES;
+ [queriedStructure removeObjectForKey:key];
+ NSPredicate *predicate = [NSPredicate predicateWithFormat:@"NOT SELF BEGINSWITH %@", [NSString stringWithFormat:@"%@%@", key, SPUniqueSchemaDelimiter]];
+ [queriedStructureKeys filterUsingPredicate:predicate];
+ [queriedStructureKeys removeObject:key];
+ }
+ }
+
+ NSString *currentDatabase = nil;
+ if ([delegate respondsToSelector:@selector(database)])
+ currentDatabase = [delegate database];
+
+ // Determine whether the database details need to be queried.
+ BOOL shouldQueryStructure = YES;
+ NSString *db_id = nil;
+
+ // If no database is selected, no need to check further
+ if(!currentDatabase || (currentDatabase && ![currentDatabase length])) {
+ shouldQueryStructure = NO;
+
+ // Otherwise, build up the schema key for the database to be retrieved.
+ } else {
+ db_id = [NSString stringWithFormat:@"%@%@%@", connectionID, SPUniqueSchemaDelimiter, currentDatabase];
+
+ // Check to see if a cache already exists for the database.
+ if ([queriedStructure objectForKey:db_id] && [[queriedStructure objectForKey:db_id] isKindOfClass:[NSDictionary class]]) {
+
+ // The cache is available. If the `mysql` or `information_schema` databases are being queried,
+ // never requery as their structure will never change.
+ // 5.5.3+ also has performance_schema meta database
+ if ([currentDatabase isEqualToString:@"mysql"] || [currentDatabase isEqualToString:@"information_schema"] || [currentDatabase isEqualToString:@"performance_schema"]) {
+ shouldQueryStructure = NO;
+
+ // Otherwise, if the forceUpdate flag wasn't supplied or evaluates to false, also don't update.
+ } else if (userInfo == nil || ![userInfo objectForKey:@"forceUpdate"] || ![[userInfo objectForKey:@"forceUpdate"] boolValue]) {
+ shouldQueryStructure = NO;
+ }
+ }
+ }
+
+ // If it has been determined that no new structure needs to be retrieved, clean up and return.
+ if (!shouldQueryStructure) {
+
+ // Update the global variables
+ [self _updateGlobalVariablesWithStructure:queriedStructure keys:queriedStructureKeys];
+
+ if (structureWasUpdated) {
+ [[NSNotificationCenter defaultCenter] postNotificationName:@"SPDBStructureWasUpdated" object:delegate];
+ }
+
+ pthread_mutex_lock(&threadManagementLock);
+ [structureRetrievalThreads removeObject:[NSThread currentThread]];
+ pthread_mutex_unlock(&threadManagementLock);
+
+ [queryPool release];
+ return;
+ }
+
+ // Retrieve the tables and views for this database from SPTablesList
+ NSMutableArray *tablesAndViews = [NSMutableArray array];
+ for (id aTable in [[delegate valueForKeyPath:@"tablesListInstance"] allTableNames]) {
+ NSDictionary *aTableDict = [NSDictionary dictionaryWithObjectsAndKeys:
+ aTable, @"name",
+ @"0", @"type",
+ nil];
+ [tablesAndViews addObject:aTableDict];
+ }
+ for (id aView in [[delegate valueForKeyPath:@"tablesListInstance"] allViewNames]) {
+ NSDictionary *aViewDict = [NSDictionary dictionaryWithObjectsAndKeys:
+ aView, @"name",
+ @"1", @"type",
+ nil];
+ [tablesAndViews addObject:aViewDict];
+ }
+
+ // Do not parse more than 2000 tables/views per db
+ if ([tablesAndViews count] > 2000) {
+ NSLog(@"%lu items in database %@. Only 2000 items can be parsed. Stopped parsing.", (unsigned long)[tablesAndViews count], currentDatabase);
+
+ pthread_mutex_lock(&threadManagementLock);
+ [structureRetrievalThreads removeObject:[NSThread currentThread]];
+ pthread_mutex_unlock(&threadManagementLock);
+
+ [queryPool release];
+ return;
+ }
+
+ // For future usage - currently unused
+ // If the affected item name and type - for example, table type and table name - were supplied, extract it.
+ NSString *affectedItem = nil;
+ NSInteger affectedItemType = -1;
+ if(userInfo && [userInfo objectForKey:@"affectedItem"]) {
+ affectedItem = [userInfo objectForKey:@"affectedItem"];
+ if([userInfo objectForKey:@"affectedItemType"])
+ affectedItemType = [[userInfo objectForKey:@"affectedItemType"] intValue];
+ else
+ affectedItem = nil;
+ }
+
+ // Delete all stored data for the database to be updated, leaving the structure key
+ [queriedStructure removeObjectForKey:db_id];
+ NSPredicate *predicate = [NSPredicate predicateWithFormat:@"NOT SELF BEGINSWITH %@", [NSString stringWithFormat:@"%@%@", db_id, SPUniqueSchemaDelimiter]];
+ [queriedStructureKeys filterUsingPredicate:predicate];
+
+ // Set up the database as an empty mutable dictionary ready for tables, and store a reference
+ [queriedStructure setObject:[NSMutableDictionary dictionary] forKey:db_id];
+ NSMutableDictionary *databaseStructure = [queriedStructure objectForKey:db_id];
+
+ NSString *currentDatabaseEscaped = [currentDatabase stringByReplacingOccurrencesOfString:@"`" withString:@"``"];
+
+ NSUInteger uniqueCounter = 0; // used to make field data unique
+ SPMySQLResult *theResult;
+
+ // Loop through the known tables and views, retrieving details for each
+ for (NSDictionary *aTableDict in tablesAndViews) {
+
+ // Extract the name
+ NSString *aTableName = [aTableDict objectForKey:@"name"];
+
+ if(!aTableName) continue;
+ if(![aTableName isKindOfClass:[NSString class]]) continue;
+ if(![aTableName length]) continue;
+
+ BOOL cancelThread = NO;
+
+ // If the thread has been cancelled, abort without saving
+ if ([[NSThread currentThread] isCancelled]) cancelThread = YES;
+
+ // Check connection state before use
+ while (!cancelThread && pthread_mutex_trylock(&connectionCheckLock)) {
+ usleep(100000);
+ if ([[NSThread currentThread] isCancelled]) {
+ cancelThread = YES;
+ break;
+ }
+ }
+
+ if (cancelThread) {
+ pthread_mutex_trylock(&connectionCheckLock);
+ pthread_mutex_unlock(&connectionCheckLock);
+ pthread_mutex_lock(&threadManagementLock);
+ [structureRetrievalThreads removeObject:[NSThread currentThread]];
+ pthread_mutex_unlock(&threadManagementLock);
+
+ [queryPool release];
+ return;
+ }
+
+ if (![self _ensureConnection]) {
+ pthread_mutex_unlock(&connectionCheckLock);
+ pthread_mutex_lock(&threadManagementLock);
+ [structureRetrievalThreads removeObject:[NSThread currentThread]];
+ pthread_mutex_unlock(&threadManagementLock);
+
+ [queryPool release];
+ return;
+ }
+ pthread_mutex_unlock(&connectionCheckLock);
+
+ // Retrieve the column details
+ theResult = [mySQLConnection queryString:[NSString stringWithFormat:@"SHOW FULL COLUMNS FROM `%@` FROM `%@`", [aTableName stringByReplacingOccurrencesOfString:@"`" withString:@"``"], currentDatabaseEscaped]];
+ if (!theResult) {
+ continue;
+ }
+ [theResult setDefaultRowReturnType:SPMySQLResultRowAsArray];
+ [theResult setReturnDataAsStrings:YES];
+
+ // Add a structure key for this table
+ NSString *table_id = [NSString stringWithFormat:@"%@%@%@", db_id, SPUniqueSchemaDelimiter, aTableName];
+ [queriedStructureKeys addObject:table_id];
+
+ // Add a mutable dictionary to the structure and store a reference
+ [databaseStructure setObject:[NSMutableDictionary dictionary] forKey:table_id];
+ NSMutableDictionary *tableStructure = [databaseStructure objectForKey:table_id];
+
+ // Loop through the fields, extracting details for each
+ for (NSArray *row in theResult) {
+ NSString *field = [row objectAtIndex:0];
+ NSString *type = [row objectAtIndex:1];
+ NSString *type_display = [type stringByReplacingOccurrencesOfRegex:@"\\(.*?,.*?\\)" withString:@"(…)"];
+ NSString *collation = [row objectAtIndex:2];
+ NSString *isnull = [row objectAtIndex:3];
+ NSString *key = [row objectAtIndex:4];
+ NSString *def = [row objectAtIndex:5];
+ NSString *extra = [row objectAtIndex:6];
+ NSString *priv = @"";
+ NSString *comment = @"";
+ if ([row count] > 7) priv = [row objectAtIndex:7];
+ if ([row count] > 8) comment = [row objectAtIndex:8];
+
+ NSString *charset = @"";
+ if (![collation isNSNull]) {
+ NSArray *a = [collation componentsSeparatedByString:@"_"];
+ charset = [a objectAtIndex:0];
+ }
+
+ // Add a structure key for this field
+ NSString *field_id = [NSString stringWithFormat:@"%@%@%@", table_id, SPUniqueSchemaDelimiter, field];
+ [queriedStructureKeys addObject:field_id];
+
+ [tableStructure setObject:[NSArray arrayWithObjects:type, def, isnull, charset, collation, key, extra, priv, comment, type_display, [NSNumber numberWithUnsignedLongLong:uniqueCounter], nil] forKey:field_id];
+ [tableStructure setObject:[aTableDict objectForKey:@"type"] forKey:@" struct_type "];
+ uniqueCounter++;
+ }
+
+ // Allow a tiny pause between iterations
+ usleep(10);
+ }
+
+ // If the MySQL version is higher than 5, also retrieve function/procedure details via the information_schema table
+ if ([mySQLConnection serverMajorVersion] >= 5) {
+ BOOL cancelThread = NO;
+
+ if ([[NSThread currentThread] isCancelled]) cancelThread = YES;
+
+ // Check connection state before use
+ while (!cancelThread && pthread_mutex_trylock(&connectionCheckLock)) {
+ usleep(100000);
+ if ([[NSThread currentThread] isCancelled]) {
+ cancelThread = YES;
+ break;
+ }
+ }
+
+ if (!cancelThread) {
+ if (![self _ensureConnection]) cancelThread = YES;
+ pthread_mutex_unlock(&connectionCheckLock);
+ };
+
+ // Return if the thread is due to be cancelled
+ if (cancelThread) {
+ pthread_mutex_trylock(&connectionCheckLock);
+ pthread_mutex_unlock(&connectionCheckLock);
+ pthread_mutex_lock(&threadManagementLock);
+ [structureRetrievalThreads removeObject:[NSThread currentThread]];
+ pthread_mutex_unlock(&threadManagementLock);
+
+ [queryPool release];
+ return;
+ }
+
+ // Retrieve the column details
+ theResult = [mySQLConnection queryString:[NSString stringWithFormat:@"SELECT * FROM `information_schema`.`ROUTINES` WHERE `information_schema`.`ROUTINES`.`ROUTINE_SCHEMA` = '%@'", [currentDatabase stringByReplacingOccurrencesOfString:@"'" withString:@"\\'"]]];
+ [theResult setDefaultRowReturnType:SPMySQLResultRowAsArray];
+
+ // Loop through the rows and extract the function details
+ for (NSArray *row in theResult) {
+ NSString *fname = [row objectAtIndex:0];
+ NSString *type = ([[row objectAtIndex:4] isEqualToString:@"FUNCTION"]) ? @"3" : @"2";
+ NSString *dtd = [row objectAtIndex:5];
+ NSString *det = [row objectAtIndex:11];
+ NSString *dataaccess = [row objectAtIndex:12];
+ NSString *security_type = [row objectAtIndex:14];
+ NSString *definer = [row objectAtIndex:19];
+
+ // Generate "table" and "field" names and add to structure key store
+ NSString *table_id = [NSString stringWithFormat:@"%@%@%@", db_id, SPUniqueSchemaDelimiter, fname];
+ NSString *field_id = [NSString stringWithFormat:@"%@%@%@", table_id, SPUniqueSchemaDelimiter, fname];
+ [queriedStructureKeys addObject:table_id];
+ [queriedStructureKeys addObject:field_id];
+
+ // Ensure that a dictionary exists for this "table" name
+ if(![[queriedStructure valueForKey:db_id] valueForKey:table_id])
+ [[queriedStructure valueForKey:db_id] setObject:[NSMutableDictionary dictionary] forKey:table_id];
+
+ // Add the "field" details
+ [[[queriedStructure valueForKey:db_id] valueForKey:table_id] setObject:
+ [NSArray arrayWithObjects:dtd, dataaccess, det, security_type, definer, [NSNumber numberWithUnsignedLongLong:uniqueCounter], nil] forKey:field_id];
+ [[[queriedStructure valueForKey:db_id] valueForKey:table_id] setObject:type forKey:@" struct_type "];
+ uniqueCounter++;
+ }
+ }
+
+ // Update the global variables
+ [self _updateGlobalVariablesWithStructure:queriedStructure keys:queriedStructureKeys];
+
+ // Notify that the structure querying has been performed
+ [[NSNotificationCenter defaultCenter] postNotificationName:@"SPDBStructureWasUpdated" object:delegate];
+
+ // Remove this thread from the processing stack
+ pthread_mutex_lock(&threadManagementLock);
+ [structureRetrievalThreads removeObject:[NSThread currentThread]];
+ pthread_mutex_unlock(&threadManagementLock);
+
+ [queryPool release];
+}
+
+- (BOOL)isQueryingDatabaseStructure
+{
+ pthread_mutex_lock(&threadManagementLock);
+ BOOL returnValue = ([structureRetrievalThreads count] > 0);
+ pthread_mutex_unlock(&threadManagementLock);
+
+ return returnValue;
+}
+
+#pragma mark -
+#pragma mark Structure information
+
+/**
+ * Returns a dict containing the structure of all available databases
+ */
+- (NSDictionary *)structure
+{
+ pthread_mutex_lock(&dataLock);
+ NSDictionary *d = [NSDictionary dictionaryWithDictionary:structure];
+ pthread_mutex_unlock(&dataLock);
+
+ return d;
+}
+
+/**
+ * Returns all keys of the db structure
+ */
+- (NSArray *)allStructureKeys
+{
+ pthread_mutex_lock(&dataLock);
+ NSArray *r = [NSArray arrayWithArray:allKeysofDbStructure];
+ pthread_mutex_unlock(&dataLock);
+
+ return r;
+}
+
+#pragma mark -
+#pragma mark SPMySQLConnection delegate methods
+
+/**
+ * Forward keychain password requests to the database object.
+ */
+- (NSString *)keychainPasswordForConnection:(id)connection
+{
+ return [delegate keychainPasswordForConnection:connection];
+}
+
+@end
+
+#pragma mark -
+#pragma mark Private API
+
+@implementation SPDatabaseStructure (Private_API)
+
+/**
+ * Update the global variables, using the data lock for multithreading safety.
+ */
+- (void)_updateGlobalVariablesWithStructure:(NSDictionary *)aStructure keys:(NSArray *)theKeys
+{
+
+ NSString *connectionID = [delegate connectionID];
+
+ // Return if the delegate indicates disconnection
+ if([connectionID length] < 2) return;
+
+ pthread_mutex_lock(&dataLock);
+
+ [structure setObject:aStructure forKey:connectionID];
+ [allKeysofDbStructure setArray:theKeys];
+
+ pthread_mutex_unlock(&dataLock);
+}
+
+/**
+ * Set up a new connection in a background thread
+ */
+- (void)_cloneConnectionFromConnection:(SPMySQLConnection *)aConnection
+{
+ NSAutoreleasePool *connectionPool = [[NSAutoreleasePool alloc] init];
+
+ pthread_mutex_lock(&connectionCheckLock);
+
+ // If a connection is already set, ensure it's idle before releasing it
+ if (mySQLConnection) {
+ pthread_mutex_lock(&threadManagementLock);
+ if ([structureRetrievalThreads count]) {
+ for (NSThread *eachThread in structureRetrievalThreads) {
+ [eachThread cancel];
+ }
+ while ([structureRetrievalThreads count]) {
+ pthread_mutex_unlock(&threadManagementLock);
+ usleep(100000);
+ pthread_mutex_lock(&threadManagementLock);
+ }
+ }
+ pthread_mutex_unlock(&threadManagementLock);
+
+ [mySQLConnection release];
+ mySQLConnection = nil;
+ }
+
+ // Create a copy of the supplied connection
+ mySQLConnection = [aConnection copy];
+
+ // Set the delegate to this instance
+ [mySQLConnection setDelegate:self];
+
+ // Trigger the connection
+ [self _ensureConnection];
+
+ pthread_mutex_unlock(&connectionCheckLock);
+
+ [connectionPool drain];
+}
+
+- (BOOL)_ensureConnection
+{
+ if (!mySQLConnection) return NO;
+
+ // Check the connection state
+ if ([mySQLConnection isConnected] && [mySQLConnection checkConnection]) return YES;
+
+ // The connection isn't connected. Check the parent connection state, and if that
+ // also isn't connected, return.
+ if (![[delegate getConnection] isConnected]) return NO;
+
+ // Copy the local port from the parent connection, in case a proxy has changed
+ [mySQLConnection setPort:[[delegate getConnection] port]];
+
+ // Attempt a connection
+ if (![mySQLConnection connect]) return NO;
+
+ // Ensure the encoding is set to UTF8
+ [mySQLConnection setEncoding:@"utf8"];
+
+ // Return success
+ return YES;
+}
+
+@end \ No newline at end of file