Various export enhancements and fixes, including:

- A new SPExportFile class, providing an abstract interface to the handling and creation of export files.
- Enables the centralisation of all file/file handle creation logic as well as better support for handling situations where files fail to be created, including files that already exist at the export location.
- New SPExportFileHandleStatus constants to support the reporting of file handle creation.
- Update SPExporter to use the new file class instead of directly using an instance of SPFileHandle.
- Add the necessary logic to deal with files that already exist on disk, by providing the user with 3 options: cancel the export, ignore the files in question or overwrite them. We might want to enhance this to make new files sequential in name to prevent overwriting. Fixes issue #742.
- New SPExportFileUtilities category, which centralises all the logic relating to writing export type headers as well as dealing with problems occurred during file/file handle creation.
- Improve feedback given on the export progress sheet during export initialisation.
- Tidy up and improve comments.

1 files changed, 8 insertions, 4 deletions

diff --git a/Source/SPDotExporter.m b/Source/SPDotExporter.m
index f10e1c97..a2db43af 100644
--- a/Source/SPDotExporter.m
+++ b/Source/SPDotExporter.m
@@ -42,6 +42,10 @@
 
 /**
  * Initialise an instance of SPDotExporter using the supplied delegate.
+ *
+ * @param exportDelegate The exporter delegate
+ *
+ * @return The initialised instance
  */
 - (id)initWithDelegate:(NSObject *)exportDelegate
 {
@@ -97,7 +101,7 @@
 	[metaString appendString:@"\trankdir = LR;\n"];
 	
 	// Write information to the file
-	[[self exportOutputFileHandle] writeData:[metaString dataUsingEncoding:NSUTF8StringEncoding]];
+	[[self exportOutputFile] writeData:[metaString dataUsingEncoding:NSUTF8StringEncoding]];
 			
 	NSMutableArray *fkInfo = [[NSMutableArray alloc] init];
 	
@@ -144,7 +148,7 @@
 		[metaString appendString:@"\t\t];\n"];
 		[metaString appendString:@"\t}\n"];
 		
-		[[self exportOutputFileHandle] writeData:[metaString dataUsingEncoding:NSUTF8StringEncoding]];
+		[[self exportOutputFile] writeData:[metaString dataUsingEncoding:NSUTF8StringEncoding]];
 		
 		// see about relations
 		columnInfo = [tableInfo objectForKey:@"constraints"];
@@ -192,10 +196,10 @@
 	[metaString appendString:@"}\n"];
 	
 	// Write information to the file
-	[[self exportOutputFileHandle] writeData:[metaString dataUsingEncoding:NSUTF8StringEncoding]];
+	[[self exportOutputFile] writeData:[metaString dataUsingEncoding:NSUTF8StringEncoding]];
 			
 	// Write data to disk
-	[[self exportOutputFileHandle] closeFile];
+	[[self exportOutputFile] close];
 	
 	// Mark the process as not running
 	[self setExportProcessIsRunning:NO];