Sets and enforces a connection timeout, and handles connection timeouts appropriately - offering to retry, reconnect, or disconnect. This fixes Issue #93, Issue #69, and Issue #77.

The gory details:
Previously, MCPKit was correctly running mysql_ping to ensure a connection still existed before running a query, and aborted the query if the connection was no longer active.However the code very rarely checked the response of this, so if a query failed subsequent queries would continue to be run and the program would end up checking non-existent results, throwing Cocoa exceptions and generally breaking.  However, mysql_ping would also use the default timeout (30 seconds) for each check - when running the (previous to r333) 14 queries to switch tables, this resulted in a long hang before the program even broke.

To exacerbate the issue, certain situations triggered a bug present in mysql_ping in the old client binaries we're using (http://bugs.mysql.com/bug.php?id=9678), causing mysql_ping to never return despite the presence of a timeout, and so causing an indefinite hang.

This issue has been fixed by:
 - Setting a new 10 second connection timeout for both new connections (Issue #69) and for mysql_pings.  Once preferences have been redesigned we'll probably make this value editable.
 - Enforce the 10 second timeout even if mysql_ping hangs by using interrupts.
 - Wrap mysql_ping in a new method to do the above and also catch re-established connections without reporting false failures.
 - When a connection has failed, prompt the user to Retry, Reconnect, or Disconnect.  Reconnect uses the original details for the old connection to establish a new connection, also attempting to preserve the current encoding.
 - Do not return control to the main loop until a connection has been reestablished (or disconnected) - this ensures the program is never in a broken state without having to rewrite all query usage.
Much of the above patches the MCPKit connection methods as necessary.

1 files changed, 28 insertions, 3 deletions

diff --git a/Source/CMMCPConnection.h b/Source/CMMCPConnection.h
index 7b379d01..3a6b4016 100644
--- a/Source/CMMCPConnection.h
+++ b/Source/CMMCPConnection.h
@@ -26,6 +26,11 @@
 #import <MCPKit_bundled/MCPKit_bundled.h>
 #import "CMMCPResult.h"
 
+// Set the connection timeout to enforce for all connections - used for the initial connection
+// timeout and ping timeouts, but not for long queries/reads/writes.
+// Probably worth moving this to a preference at some point.
+#define SP_CONNECTION_TIMEOUT 10
+
 @interface NSObject (CMMCPConnectionDelegate)
 
 - (void)willQueryString:(NSString *)query;
@@ -34,11 +39,31 @@
 @end
 
 @interface CMMCPConnection : MCPConnection {
+	IBOutlet NSWindow *connectionErrorDialog;
+	NSWindow *parentWindow;
 	id	delegate;
+
+	BOOL nibLoaded;
+	NSString *connectionLogin;
+	NSString *connectionPassword;
+	NSString *connectionHost;
+	int connectionPort;
+	NSString *connectionSocket;
 }
 
-- (CMMCPResult *)queryString:(NSString *) query;
-- (void)setDelegate:(id)object;
-- (NSTimeZone *)timeZone;
+- (id) init;
+- (id) initToHost:(NSString *) host withLogin:(NSString *) login password:(NSString *) pass usingPort:(int) port;
+- (id) initToSocket:(NSString *) socket withLogin:(NSString *) login password:(NSString *) pass;
+- (void) initSPExtensions;
+- (BOOL) connectWithLogin:(NSString *) login password:(NSString *) pass host:(NSString *) host port:(int) port socket:(NSString *) socket;
+- (void) disconnect;
+- (BOOL) reconnect;
+- (IBAction) closeSheet:(id)sender;
+- (void) setParentWindow:(NSWindow *)theWindow;
+- (CMMCPResult *) queryString:(NSString *) query;
+- (BOOL) checkConnection;
+- (void) setDelegate:(id)object;
+- (NSTimeZone *) timeZone;
+- (BOOL) pingConnection;
 
 @end