NSArray with componentsSeparatedByString memory leak - objective-c

I'm having problems with memory leaks with this function. I thought creating an NSArray with componentsSeparatedByString was autorelease but instruments seems to indicate a leak at the NSArray aPair. Why would it indicate a leak there and not also at the other NSArrays created in the same way?
-(void) checkRequest: (NSString *)request view:(UIViewController *)theView webView:(UIWebView *)wView
{
//NSLog(#"JSResponder - checkRequest()");
NSString *aRequest = [NSString stringWithString:request];
NSArray *urlArray = [aRequest componentsSeparatedByString:#"?"];
if([urlArray count] > 1)
{
NSString *paramsString = [urlArray lastObject];
NSString *cmd = #"";
NSArray *urlParamsArray = [paramsString componentsSeparatedByString:#"&"];
int numCommands = [urlParamsArray count];
NSMutableDictionary *paramsWithNames = [[NSMutableDictionary alloc ] initWithCapacity:numCommands];
for (NSString *elementPair in urlParamsArray)
{
NSArray *aPair = [elementPair componentsSeparatedByString:#"="];
NSString *aKey = [aPair objectAtIndex:0];
NSString *aParam = [aPair objectAtIndex:1];
if([aKey compare:#"_command"] == NSOrderedSame)
{
cmd = aParam;
}
else
{
[paramsWithNames setValue: aParam forKey:aKey];
}
}
[self executeCommand: cmd withParams: paramsWithNames view:theView webView:wView];
[paramsWithNames release];
}
}
This function get called by the following:
- (void)pullJSEvent:(NSTimer*)theTimer
{
NSLog(#"MainView - pullJSEvent()");
NSString *jsCall = [NSString stringWithString:#"if(typeof checkOBJCEvents == 'function'){checkOBJCEvents();}"];
NSString *jsAnswer = [[webView stringByEvaluatingJavaScriptFromString:jsCall] retain];
if([jsAnswer compare:#"none"] != NSOrderedSame)
{
//NSLog(#" answer => %#", jsAnswer);
[jsResponder checkRequest:jsAnswer view:(UIViewController *)self webView:self.webView];
}
[jsAnswer release];
}
Thank-you

You're going to have to dig a bit deeper with the Leaks instrument. You're leaking one of the strings in the array, not the array itself. Leaks indicates that line because that's where the strings in the array are allocated.
Go into Leaks, look at a leaked instance, and click that little arrow button. You'll see all the retains and releases of the leaked object, which should point you to the problem.

Related

run applescript from cocoa app stopped working

This code had been working fine until just recently. I hadn't' changed anything nor upgraded my system and I'm completely flummoxed.
I've been using it for 6 years and now it dies on me.
Is there an easier or better way of running an applescript from within a cocoa application? At this point I'm happy to pay to fix this problem!
utils.h
#import <Foundation/Foundation.h>
#interface Utils : NSObject
// Runs an applescript with a given map of variables (name/value)
+ (NSArray *)runApplescript:(NSString *)source withVariables:(NSDictionary *)variables;
// Runs an applescript from a file pathwith a given map of variables
// (name/value)
+ (NSArray *)runApplescriptFromFile:(NSString *)scriptName withVariables:(NSDictionary *)variables;
+ (NSArray *)arrayFromDescriptor:(NSAppleEventDescriptor *)descriptor;
// String is empty or only has white characters (space, tab...)
+ (BOOL)stringIsEmptyOrWhite:(NSString *)string;
#end
Utils.M
#import "Utils.h"
#implementation Utils
+ (NSArray *)arrayFromDescriptor:(NSAppleEventDescriptor *)descriptor {
// Enumerate the apple descriptors (lists) returned by the applescript and
// make them into arrays
NSMutableArray *returnArray = [NSMutableArray array];
NSInteger counter, count = [descriptor numberOfItems];
for (counter = 1; counter <= count; counter++) {
NSAppleEventDescriptor *desc = [descriptor descriptorAtIndex:counter];
if (nil != [desc descriptorAtIndex:1]) {
[returnArray addObject:[Utils arrayFromDescriptor:desc]];
} else {
NSString *stringValue = [[descriptor descriptorAtIndex:counter] stringValue];
if (nil != stringValue) {
[returnArray addObject:stringValue];
} else {
[returnArray addObject:#""];
}
}
}
return returnArray;
}
+ (NSString *)escapeCharacters:(NSString *)string {
return [string stringByReplacingOccurrencesOfString:#"\"" withString:#"\\\""];
}
+ (NSArray *)runApplescript:(NSString *)source withVariables:(NSDictionary *)variables {
NSString *input = #"";
NSArray *variableNames = [variables allKeys];
// Transform the dictionary of names/values to set sentences of applescript
for (NSString *variableName in variableNames) {
NSObject *variableValue = [variables objectForKey:variableName];
if ([variableValue isKindOfClass:[NSString class]]) {
input =
[input stringByAppendingString:[NSString stringWithFormat:#"set %# to (\"%#\" as text)\n", variableName,
[Utils escapeCharacters:variableValue], nil]];
} else if ([variableValue isKindOfClass:[NSNumber class]]) {
input = [input stringByAppendingString:[NSString stringWithFormat:#"set %# to (%# as integer)\n",
variableName, variableValue, nil]];
} else if ([variableValue isKindOfClass:[NSArray class]]) {
// Initialize a list
NSString *entry;
NSArray *values = (NSArray *)variableValue;
input = [input stringByAppendingString:[NSString stringWithFormat:#"set %# to {", variableName]];
BOOL first = TRUE;
for (entry in values) {
if (!first) {
input = [input stringByAppendingString:#", "];
}
input = [input
stringByAppendingString:[NSString stringWithFormat:#"\"%#\"", [Utils escapeCharacters:entry], nil]];
first = FALSE;
}
input = [input stringByAppendingString:#"}\n"];
}
}
NSString *finalScript = [input stringByAppendingString:[NSString stringWithFormat:#"\n\n%#", source]];
NSLog(#"Final script: %#", finalScript);
NSAppleScript *script = [[NSAppleScript alloc] initWithSource:finalScript];
NSDictionary *error;
NSAppleEventDescriptor *descriptor = [script executeAndReturnError:&error];
NSLog(#"applescript error: %#", [error description]);
// Transform the return value of applescript to nested nsarrays
return [Utils arrayFromDescriptor:descriptor];
}
+ (NSArray *)runApplescriptFromFile:(NSString *)scriptName withVariables:(NSDictionary *)variables {
NSString *scriptPath = [[NSBundle mainBundle] pathForResource:scriptName ofType:#"applescript"];
NSString *scriptSource =
[[NSString alloc] initWithContentsOfFile:scriptPath encoding:NSASCIIStringEncoding error:nil];
return [Utils runApplescript:scriptSource withVariables:variables];
}
+ (BOOL)stringIsEmptyOrWhite:(NSString *)string {
string = [string stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceCharacterSet]];
return [string isEqualToString:#""];
}
#end
Easier, yes, although whether that’s your actual problem is another question.
http://appscript.sourceforge.net/asoc.html
I assume you’ve already got other details, including sandboxing and hardening settings and plist entries, taken care of. (Recent Xcode upgrades also had a habit of breaking it when auto-upgrading your project files, by turning on hardening for you so Apple events can’t get out.)

"Can't allocate region" malloc error when running millions of iterations of loop

Thanks to a lot of help I've received here on SO, I've gotten an algorithm to check a list of around 15,000 8-letter words for any partial anagrams, against a list of around 50,000 total words (so I suppose a total of 108 million iterations). I call this method once for each comparison (so 750 million times). I'm getting the following error, always somewhere in the midst of the 119th iteration through the 1,350 there should be:
AnagramFINAL(2960,0xac8c7a28) malloc: *** mmap(size=2097152) failed (error code=12)
*** error: can't allocate region
*** set a breakpoint in malloc_error_break to debug
I've narrowed the memory issue down to being a huge number of allocated CFStrings (immutable). Any idea what I can do to remedy the issue? I'm using ARC and an #autoreleasepool, not sure what else I could do, it seems something isn't being released when it should be.
AnagramDetector.h
#import <Foundation/Foundation.h>
#interface AnagramDetector : NSObject {
NSDictionary *allEightLetterWords;
NSDictionary *allWords;
NSFileManager *fileManager;
NSArray *paths;
NSString *documentsDirectory;
NSString *filePath;
}
- (BOOL) does: (NSString *) longWord contain: (NSString *) shortWord;
- (NSDictionary *) setupAllWordList;
- (NSDictionary *) setupEightLetterWordList;
- (void) saveDictionary: (NSMutableDictionary *)currentArray;
#end
AnagramDetector.m
#implementation AnagramDetector
- (id) init {
self = [super init];
if (self) {
fileManager = [NSFileManager defaultManager];
paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
documentsDirectory = [paths objectAtIndex:0];
}
return self;
}
- (BOOL) does: (NSString *) longWord contain: (NSString *) shortWord {
#autoreleasepool {
NSMutableString *longerWord = [longWord mutableCopy];
for (int i = 0; i < [shortWord length]; i++) {
NSString *letter = [shortWord substringWithRange: NSMakeRange(i, 1)];
NSRange letterRange = [longerWord rangeOfString: letter];
if (letterRange.location != NSNotFound) {
[longerWord deleteCharactersInRange: letterRange];
} else {
return NO;
}
}
return YES;
}
}
- (NSDictionary *) setupAllWordList {
#autoreleasepool {
NSString *fileWithAllWords = [[NSBundle mainBundle] pathForResource:#"AllDefinedWords" ofType:#"plist"];
allWords = [[NSDictionary alloc] initWithContentsOfFile: fileWithAllWords];
NSLog(#"Total number of words: %d.", [allWords count]);
}
return allWords;
}
- (NSDictionary *) setupEightLetterWordList {
#autoreleasepool {
NSString *fileWithEightWords = [[NSBundle mainBundle] pathForResource:#"AllDefinedEights" ofType:#"plist"];
allEightLetterWords = [[NSDictionary alloc] initWithContentsOfFile: fileWithEightWords];
NSLog(#"Total number of words: %d.", [allEightLetterWords count]);
}
return allEightLetterWords;
}
- (void) saveDictionary: (NSMutableDictionary *)currentArray {
#autoreleasepool {
filePath = [documentsDirectory stringByAppendingPathComponent: #"A.plist"];
[fileManager createFileAtPath:filePath contents: nil attributes: nil];
[currentArray writeToFile: filePath atomically:YES];
[currentArray removeAllObjects];
}
}
#end
Code running on launch (inside AppDelegate for now, since no VC):
#autoreleasepool {
AnagramDetector *detector = [[AnagramDetector alloc] init];
NSDictionary *allWords = [[NSDictionary alloc] initWithDictionary:[detector setupAllWordList]];
NSDictionary *eightWords = [[NSDictionary alloc] initWithDictionary:[detector setupEightLetterWordList]];
int remaining = [eightWords count];
for (NSString *currentEightWord in eightWords) {
if (remaining % 10 == 0) NSLog(#"%d ::: REMAINING :::", remaining);
for (NSString *currentAllWord in allWords) {
if ([detector does: [eightWords objectForKey: currentEightWord] contain: [allWords objectForKey: currentAllWord]]) {
// NSLog(#"%# ::: CONTAINS ::: %#", [eightWords objectForKey: currentEightWord], [allWords objectForKey: currentAllWord]);
}
}
remaining--;
}
}
The problem seems to be that a lot of autoreleased objects fill up the memory waiting to be released. So a solution is to add your own autorelease pool scope to collect autoreleased objects and release them sooner.
I suggest that you do something like this:
for (NSString *currentEightLetterWord in [eightLetterWordsDictionary allKeys]) {
#autoreleasepool {
for (NSString *currentWord in [allWordsDictionary allKeys]) {
}
}
}
Now all autoreleased objects inside #autoreleasepool { .. } will be released for each iteration of the outer loop.
As you see ARC might save you from thinking about most reference counting and memory management issues but objects can still end up in autorelease pools with ARC when using methods that directly or indirectly create autoreleased objects.
An alternative solution that I don't really recommend is to try to avoid using method that will use autorelease. Then does:contain: could awkwardly be rewritten to something like this:
- (BOOL) does: (NSString* ) longWord contain: (NSString *) shortWord {
NSMutableString *haystack = [longWord mutableCopy];
NSMutableString *needle = [shortWord mutableCopy];
while([haystack length] > 0 && [needle length] > 0) {
NSMutableCharacterSet *set = [[NSMutableCharacterSet alloc] init];
[set addCharactersInRange:NSMakeRange([needle characterAtIndex:0], 1)];
if ([haystack rangeOfCharacterFromSet:set].location == NSNotFound) return NO;
haystack = [haystack mutableCopy];
[haystack deleteCharactersInRange:NSMakeRange(0, [haystack rangeOfCharacterFromSet: set].location)];
needle = [needle mutableCopy];
[needle deleteCharactersInRange:NSMakeRange(0, 1)];
}
return YES;
}

release of previously deallocated object issue

I have a function which use for read one single line from a csv file.
But I got a release of previously deallocated object error, or sometimes the it is "double free" error.
I try to track down which object causes this error base on the error memory address, but I failed to do this.
Here's the code:
#interface CSVParser : NSObject {
NSString *fileName;
NSString *filePath;
NSString *tempFileName;
NSString *tempFilePath;
//ReadLine control
BOOL isFirstTimeLoadFile;
NSString *remainContent;
}
#property(nonatomic,retain) NSString *fileName;
#property(nonatomic,retain) NSString *filePath;
#property(nonatomic,retain) NSString *tempFileName;
#property(nonatomic,retain) NSString *tempFilePath;
#property(nonatomic,retain) NSString *remainContent;
-(id)initWithFileName:(NSString*)filename;
-(BOOL)checkAndCopyFile:(NSString *)filename;
-(BOOL)checkAndDeleteTempFile;
-(NSString*)readLine;
-(NSArray*)breakLine:(NSString*)line;
#end
#implementation CSVParser
#synthesize fileName;
#synthesize filePath;
#synthesize tempFileName;
#synthesize tempFilePath;
#synthesize remainContent;
-(id)initWithFileName:(NSString *)filename{
//ReadLine control
isFirstTimeLoadFile = TRUE;
self.fileName = filename;
self.tempFileName = [[NSString alloc] initWithFormat:#"temp_%#",fileName];
NSArray *documentPaths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentDir = [documentPaths objectAtIndex:0];
self.filePath = [documentDir stringByAppendingPathComponent:fileName];
self.tempFilePath = [documentDir stringByAppendingPathComponent:tempFileName];
if ([self checkAndCopyFile:fileName]) {
return self;
}else {
return #"Init Failure";
}
}
-(BOOL)checkAndCopyFile:(NSString *)filename{
BOOL isFileExist;
NSError *error = nil;
NSFileManager *fileManger = [NSFileManager defaultManager];
isFileExist = [fileManger fileExistsAtPath:filePath];
if (isFileExist) {
//Create a temp file for reading the line.
[fileManger copyItemAtPath:filePath toPath:tempFilePath error:&error];
return TRUE;
}else {
return FALSE;
}
}
-(NSString*)readLine{
NSError *error = nil;
//Read the csv file and save it as a string
NSString *tempFirstLine = [[[NSString alloc] init] autorelease];
NSString *stringFromFileAtPath = [[NSString alloc] init];
if (isFirstTimeLoadFile) {
NSLog(#"Into First Time");
stringFromFileAtPath = [NSString stringWithContentsOfFile:tempFilePath
encoding:NSUTF8StringEncoding
error:&error];
isFirstTimeLoadFile = FALSE;
}else {
NSLog(#"Not First Time");
NSLog(#"Not First Time count:%d",[remainContent retainCount]);
stringFromFileAtPath = remainContent;
remainContent = nil;
}
if ([stringFromFileAtPath isEqualToString:#""]) {
[stringFromFileAtPath release];
return #"EOF";
}
//Get the first line's range
NSRange firstLineRange = [stringFromFileAtPath rangeOfString:#"\n"];
//Create a new range for deletion. This range's lenght is bigger than the first line by 1.(Including the \n)
NSRange firstLineChangeLineIncludedRange;
if (stringFromFileAtPath.length > 0 && firstLineRange.length == 0) {
//This is the final line.
firstLineRange.length = stringFromFileAtPath.length;
firstLineRange.location = 0;
firstLineChangeLineIncludedRange = firstLineRange;
}else {
firstLineRange.length = firstLineRange.location;
firstLineRange.location = 0;
firstLineChangeLineIncludedRange.location = firstLineRange.location;
firstLineChangeLineIncludedRange.length = firstLineRange.length + 1;
}
//Get the first line's content
tempFirstLine = [stringFromFileAtPath substringWithRange:firstLineRange];
remainContent = [stringFromFileAtPath stringByReplacingCharactersInRange:firstLineChangeLineIncludedRange withString:#""];
[stringFromFileAtPath release];
error = nil;
return tempFirstLine;
}
And the following code shows how I use the class above:
CSVParser *csvParser = [[CSVParser alloc] initWithFileName:#"test.csv"];
BOOL isFinalLine = FALSE;
while (!isFinalLine) {
NSString *line = [[NSString alloc] init];
line = [csvParser readLine];
if ([line isEqualToString:#"EOF"]) {
isFinalLine = TRUE;
}
NSLog(#"%#",line);
[line release];
}
[csvParser release];
If I run the code, and finish the csv parsing, the App's main function will give me the double free error when it try to free the autorelease pool."* __NSAutoreleaseFreedObject(): release of previously deallocated object (0x6a26050) ignored"
NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];
int retVal = UIApplicationMain(argc, argv, nil, nil);
Could someone help me solve this issue?
Thank you!
[pool release];
Do not use -retainCount.
The absolute retain count of an object is meaningless.
You should call release exactly same number of times that you caused the object to be retained. No less (unless you like leaks) and, certainly, no more (unless you like crashes).
See the Memory Management Guidelines for full details.
There are a few problems in your code:
you aren't following the correct init pattern. You should have a self = [super init...]; if (self) {...} in there somewhere.
tempFileName is a retain property and you assign it the result of alloc/init. It will be leaked.
An immutable empty string ([[NSString alloc] init]) is pretty much never useful. And, in fact, stringFromFileAtPath is being leaked (technically -- implementation detail wise there is an empty immutable singleton string and thus, no real leak, but.... still...)
Finally, the crash: your readLine method correctly returns an autoreleased object. Yet, your while() loop consuming the return value of readLine is also releaseing that return value, leading to a double-release and an attempt to free that which was already freed.
You should "build and analyze" your code. I bet the llvm static analyzer would identify most, if not all, of the problems I mentioned above (and probably some more I missed).
When building with the analyzer, do you have either "all messages" or "analyzer issues only" selected in the Build window? Because, looking at the code, I'm surprised the analyzer didn't catch the obvious problem with stringFromFileAtPath.
Excerpting the code, you have the following lines that manipulate stringFromFileAtPath:
NSString *stringFromFileAtPath = [[NSString alloc] init];
....
stringFromFileAtPath = [NSString stringWithContentsOfFile:tempFilePath
encoding:NSUTF8StringEncoding
error:&error];
....
stringFromFileAtPath = remainContent;
....
[stringFromFileAtPath release];
And remainContent is set by:
remainContent = [stringFromFileAtPath stringByReplacingCharactersInRange:firstLineChangeLineIncludedRange
withString:#""];
You are releasing an autoreleased object. By memory keeps going up, how are you measuring it? Don't use Activity Monitor as it is nearly as useless to developers as retainCount is misleading. Use Instruments.
Your tempFirstLine NSString object is declared with autorelease, and is returned as your NSString line, which is then released.
Try using this:
while (!isFinalLine) {
NSString *line = [csvParser readLine];
if ([line isEqualToString:#"EOF"]) {
isFinalLine = TRUE;
}
NSLog(#"%#",line);
}
Replac this:
NSString *stringFromFileAtPath = [[NSString alloc] init];
with this:
NSString *stringFromFileAtPath = nil;
and get rid of the [stringFromFileAtPath release] statements.
The first line creates a pointer to a new string object that you never use, because you immediately overwrite the pointer with a pointer to string objects from elsewhere, which you don't need to release because you don't own them/didn't create them. Since you are releasing them, you're getting a crash.
You make the same mistake with tempFirstLine.

Objective C - UITableView after calling reloadData my object properties are null/nil

I have a ViewController defined as follows:
#interface SectionController : UITableViewController {
NSMutableArray *sections;
}
- (void) LoadSections;
When LoadSection is call it makes a call to NSURLConnection to load a url which in turn calls
- (void)connectionDidFinishLoading:(NSURLConnection *)connection {
NSString *responseString = [[NSString alloc] initWithData:responseData encoding:NSUTF8StringEncoding];
[connection release];
[responseData release];
NSDictionary *results = [responseString JSONValue];
NSMutableArray *jSections = [results objectForKey:#"Items"];
sections = [NSMutableArray array];
for (NSArray* jSection in jSections)
{
Section* section = [Section alloc];
section.Id = [jSection objectForKey:#"Id"];
section.Description = [jSection objectForKey:#"Description"];
section.Image = [jSection objectForKey:#"Image"];
section.Parent = [jSection objectForKey:#"Parent"];
section.ProductCount = [jSection objectForKey:#"ProductCount"];
[sections addObject:section];
[section release];
}
[jSections release];
[results release];
[delegate sectionsLoaded];
[self.view reloadData];
}
The data parses correctly and I now have sections filled with many items.
Calling [self.view reloadData] forces a callback to the delegate method cellForRowAtIndexPath which should then present the data into the cell however its at this point that sections is now nil again.
Can someone please point out my mistake? I must admit I am a newbie to objective c and it probably a pointer issue. What is need to do is retain the value of sections after calling reloadData.
Many thanks.
Seeing the new code the problem is obvious:
sections = [NSMutableArray array];
should become
[sections release];
sections = [[NSMutableArray alloc] init];
note that the array does not become again "nil", is instead deallocated and you get an invalid reference, which might (should) generate a crash on dereferencing.
I suggest you to read some articles on reference counted memory management as it might be not obvious if you are new to Objective-C, and often leads to mistake (i.e: autorelease is not magic at all)
best way to avoid all memory leaks here is just simply use #property (nonatomic, retain) NSMutableArray *sections; by using property you can be sure that all men management works will be correctly managed by system. Just don't forget that property retains value when you doing setSections:, so that you need to pass autoreleased object here.
self.sections = [NSMutableArray array];
...
[self.sections addObject:section];
Also to avoid all problem try to make all objects which should live only in this method autorelease. Like this:
- (void)connectionDidFinishLoading:(NSURLConnection *)connection {
NSString *responseString = [[[NSString alloc] initWithData:responseData encoding:NSUTF8StringEncoding] autorelease];
NSDictionary *results = [responseString JSONValue];
NSMutableArray *jSections = [results objectForKey:#"Items"];
self.sections = [NSMutableArray array];
for (NSArray* jSection in jSections) {
Section* section = [[[Section alloc] init] autorelease];
section.Id = [jSection objectForKey:#"Id"];
section.Description = [jSection objectForKey:#"Description"];
section.Image = [jSection objectForKey:#"Image"];
section.Parent = [jSection objectForKey:#"Parent"];
section.ProductCount = [jSection objectForKey:#"ProductCount"];
[self.sections addObject:section];
}
[delegate sectionsLoaded];
[self.view reloadData];
}
And also most of object you trying to release already autoreleased:
all params passed into your method shouldn't be released manually, check I think JSONValue also should returns autoreleased object and anything you getting by enumerating or by call objectForKey:

Is there anything wrong with my code?

-(void)processGlyph:(int)glyphOne withGlyph:(int)glyphTwo
{
answer = glyphOne + glyphTwo;
NSString *tempText = [[NSString alloc] init];
tempText = [NSString stringWithFormat:#"%i",answer];
[self dispatchText:tempText];
[tempText release];
}
-(void)checkReadyToProcess
{
if (count >= 2) {
[self processGlyph:firstGlyph withGlyph:secondGlyph];
}
}
-(void)dispatchText:(NSString *) theText
{
answerText.text = theText;
}
Yes. It is here:
NSString *tempText = [[NSString alloc] init];//leaked
tempText = [NSString stringWithFormat:#"%i",answer];//creates new autoreleased object
...
[tempText release]; //causes an eventual crash
You are allocating an NSString, replacing the variable with an autoreleased NSString, and then releasing the autoreleased NSString. This will lead to a memory leak (from the original NSString) and a crash from over-releasing.
Instead, just do:
NSString *tempText = [NSString stringWithFormat:#"%i",answer];
You don't have to release it.