Threading/notification improvments

git-svn-id: svn+ssh://svn.gna.org/svn/gnustep/libs/sqlclient/trunk@38447 72102866-910b-0410-8b05-ffd578937521

ChangeLog

@@ -1,11 +1,28 @@
+2015-04-01 Richard Frith-Macdonald  <rfm@gnu.org>
+
+	* SQLClient.h:
+	* Postgres.m:
+	Fixup notification posting to be asynchronous using the default
+	notification queue for the thread so that the notifications do
+	not get delivered while the query/statement at which they were
+	detected is still in progress.
+	Add method to explicitly grab/release the client for the current
+	thread.
+
 2015-03-11 Richard Frith-Macdonald  <rfm@gnu.org>
-	* SQLClientPool.m: Fixup for ewxposing prepare method
+
+	* SQLClientPool.m: Fixup for exposing prepare method
 	* SQLClient.h:
 	* SQLClient.m:
 	* Postgres.m:
 	* testPostgres.m:
 	Add simple array support for char/varchar/text, integer/real,
-	timestamp, bool and bytea.
+	timestamp, bool and bytea.  When a query returns an array of
+	one of these types, the resulting object is an NSArray containing
+	the database array elements rather than an NSString containing the
+	string literal representation of the database array.
+	Also added a method to convert an NSArray to a string literal
+	representation of a database array.
 
 2015-03-02 Richard Frith-Macdonald  <rfm@gnu.org>
 

Postgres.m

@@ -35,6 +35,7 @@
 #import	<Foundation/NSFileHandle.h>
 #import	<Foundation/NSProcessInfo.h>
 #import	<Foundation/NSNotification.h>
+#import	<Foundation/NSNotificationQueue.h>
 #import	<Foundation/NSUserDefaults.h>
 #import	<Foundation/NSMapTable.h>
 #import	<Foundation/NSLock.h>
@@ -279,8 +280,8 @@ connectQuote(NSString *str)
 
 - (void) _checkNotifications
 {
-  static NSNotificationCenter   *nc;
-  PGnotify                      *notify;
+  NSNotificationQueue   *nq = nil;
+  PGnotify              *notify;
 
   while ((notify = PQnotifies(connection)) != 0)
     {
@@ -328,11 +329,14 @@ connectQuote(NSString *str)
                                           userInfo: (NSDictionary*)userInfo];
           [name release];
           [userInfo release];
-          if (nil == nc)
+
+          if (nil == nq)
             {
-              nc = [[NSNotificationCenter defaultCenter] retain];
+              nq = [NSNotificationQueue defaultQueue];
             }
-          [nc postNotification: n];
+          /* Post asynchronously
+           */
+          [nq enqueueNotification: n postingStyle: NSPostASAP];
         }
       NS_HANDLER
         {
@@ -523,9 +527,9 @@ static unsigned int trim(char *str)
             }
           if ('\"' == *p)
             {
-              *p++ = '\0';
+              *p = '\0';
             }
-          if (len == (p - start + 1))
+          if (len == (p - start))
             {
               v = [[NSString alloc] initWithUTF8String: start];
             }
@@ -562,6 +566,7 @@ static unsigned int trim(char *str)
                                 freeWhenDone: YES];
                 }
             }
+          *p++ = '\"';
         }
       else
         {
@@ -677,6 +682,7 @@ static unsigned int trim(char *str)
       case 1002:        // CHAR ARRAY
       case 1009:        // TEXT ARRAY
       case 1015:        // VARCHAR ARRAY
+      case 1263:        // CSTRING ARRAY
         if ('{' == *p)
           {
             NSMutableArray      *a;
@@ -1212,7 +1218,7 @@ static unsigned int trim(char *str)
       else if ([o isKindOfClass: [NSDate class]])
         {
           [s appendString: [self quote: (NSString*)o]];
-          [s appendString: @"::timestamp"];
+          [s appendString: @"::timestamp with time zone"];
         }
       else if ([o isKindOfClass: [NSData class]])
         {

SQLClient.h

@@ -488,6 +488,13 @@ SQLCLIENT_PRIVATE
  */
 - (void) begin;
 
+/** This grabs the receiver for use by the current thread.<br />
+ * If limit is nil or in the past, makes a single immediate attempt.<br />
+ * Returns NO if it fails to obtain a lock by the specified date.<br /> 
+ * Must be matched by an -unlock if it succeeds.
+ */
+- (BOOL) lockBeforeDate: (NSDate*)limit;
+
 /**
  * <p>Build an sql query string using the supplied arguments.
  * </p>
@@ -787,7 +794,12 @@ SQLCLIENT_PRIVATE
  * YYYY-MM-DD hh:mm:ss.mmm ?ZZZZ<br />
  * NSData objects are not quoted ... they must not appear in queries, and
  * where used for insert/update operations, they need to be passed to the
- * -backendExecute: method unchanged.
+ * -backendExecute: method unchanged.<br />
+ * NSArray and NSSet objects are quoted as sets containing the quoted
+ * elements from the array/set.  If you want to use SQL arrays (and your
+ * database backend supports it) you must explicitly use the
+ * -quoteArray:toString:quotingString: to convert an NSArray to a literal
+ * database array representation.
  */
 - (NSString*) quote: (id)obj;
 
@@ -928,6 +940,10 @@ SQLCLIENT_PRIVATE
 		     recordType: (id)rtype
 		       listType: (id)ltype;
 
+/** Releases a lock previously obtained using -lockbeforeDate:
+ */
+- (void) unlock;
+
 /**
  * Return the database user for this instance (or nil).
  */
@@ -1088,7 +1104,8 @@ SQLCLIENT_PRIVATE
  * which don't support asynchronous notifications.<br />
  * If a backend <em>does</em> support asynchronous notifications,
  * it should do so by posting NSNotification instances to
- * [NSNotificationCenter defaultCenter] using the SQLClient instance as
+ * [NSNotificationQueue defaultQueue] with the posting style NSPostASAP
+ * (to post asynchronously) and using the SQLClient instance as
  * the notification object and supplying any payload as a string using
  * the 'Payload' key in the NSNotification userInfo dictionary.
  * The userInfo dictionary should also contain a boolean (NSNumber) value,
@@ -1182,11 +1199,14 @@ SQLCLIENT_PRIVATE
  * as an action by this SQLClient instance.<br />
  * If the 'Payload' value is not nil, then it is a string providing extra
  * information about the notification.<br />
- * NB. At the point when the observer is notified about an event the
- * database client object will be locked and may not be used to query
- * or modify the database (typically a database query will already be
- * in progress).  The method handling the notification must therefore
- * handle any database operations in a later timeout.
+ * Notifications are posted asynchronously using the default notification
+ * queue for the current thread, so they should be delivered to the
+ * observer after the database statement in which they were detected
+ * has completed.  However, delivery of the notification could still
+ * occur inside a transaction is the -begin and -commit statements
+ * are used.  For this reason, observing code may want to use the
+ * -lockBeforeDate: -isInTransaction and -unlock methods to ensure
+ * that they don't interfere with ongoing transactions.
  */
 - (void) addObserver: (id)anObserver
             selector: (SEL)aSelector

SQLClient.m

@@ -1341,6 +1341,15 @@ static int	        poolConnections = 0;
   return nil;
 }
 
+- (BOOL) lockBeforeDate: (NSDate*)limit
+{
+  if (nil == limit)
+    {
+      return [lock tryLock];
+    }
+  return [lock lockBeforeDate: limit];
+}
+
 - (SQLClient*) longestIdle: (SQLClient*)other
 {
   NSTimeInterval        t0;
@@ -2015,6 +2024,11 @@ static int	        poolConnections = 0;
   return result;
 }
 
+- (void) unlock
+{
+  [lock unlock];
+}
+
 - (NSString*) user
 {
   return _user;

testPostgres.m

@@ -260,7 +260,7 @@ main()
         @"extra2 varchar[],"
         @"extra3 bytea[],"
         @"extra4 boolean[],"
-        @"extra5 timestamp[]"
+        @"extra5 timestamp with time zone[]"
 	@")",
 	nil];