Clear matplotlib's font cache file at launch to prevent sandboxing vi…

…olations when the app bundle was moved since the last launch. See

http://stackoverflow.com/questions/19675235/matplotlib-output-not-showing-up-inline-in-ipython-notebook-despite-pylab-inli/19676283#19676283

for details.

IPython Notebook/Notebook Controller/NotebookWindowController.m

@@ -218,6 +218,8 @@ - (IBAction)openNotebooksFolder:(id)sender
 
 - (BOOL)launchNotebookServerTask
 {
+	[self clearApplicationBundleLocationDependentCacheFiles];
+
 	NSURL *virtualEnvPythonURL = [[NSBundle mainBundle] URLForResource:@"python" withExtension:nil subdirectory:@"virtualenv/bin"];
 	NSURL *launchScriptURL = [[NSBundle mainBundle] URLForResource:@"launch-ipython" withExtension:@"py" subdirectory:@"virtualenv/bin"];
 	NSAssert(launchScriptURL, NSLocalizedString(@"Unable to determine url to launch-ipython.py script in resources", nil));
@@ -256,6 +258,22 @@ - (BOOL)launchNotebookServerTask
 }
 
 
+- (void)clearApplicationBundleLocationDependentCacheFiles
+{
+	NSURL *homeDirectoryUrl = [NSURL fileURLWithPath:NSHomeDirectory()];
+	NSURL *matplotlibFontListCacheUrl = [homeDirectoryUrl URLByAppendingPathComponent:@".matplotlib/fontList.cache"];
+
+	NSFileManager *fm = [NSFileManager defaultManager];
+	if ([fm fileExistsAtPath:[matplotlibFontListCacheUrl path]]) {
+		NSLog(@"Removing cache file %@", [matplotlibFontListCacheUrl path]);
+		NSError *error = nil;
+		if (![fm removeItemAtURL:matplotlibFontListCacheUrl error:&error]) {
+			NSLog(@"Unable to remove cache file: %@", error);
+		}
+	}
+}
+
+
 - (NSString *)customPythonPath
 {
     if (![self.pythonPathURLs count]) {