Borkware Quickies

Enabling ARC (General->General)

Sat, 12 May 2012 20:01:46 UTC

Turn on ARC at the command line by feeding the compiler the -fobjc-arc flag.

Git Logging Options (git->General)

Fri, 04 May 2012 22:28:25 UTC

git log [options] [--] [path]

-p — show the diff (patch)
-# — limit output (e.g. -23 to last 23 entries)
--since / --until — commits more recent (or older) than given date
--stat — abbreviated stats (adds/deletes, modified files)
--pretty=thing — Make output pretty. Things include oneline, short, medium, full, fuller, (no fullest), email, raw, format:, tformat: . use tformat if you want a newline at the end of the log
--graph — draw those funky git branch gtaphs
--author / --committer — filter on specific dude / dudette
--grep — filter on keywords in commit messages
--all-match — Turn multiple predicates from OR into AND

Format Options

%H / %h — hash (shortened)
%T / %t — tree hash (shortened)
%P / %p — parent hash (shortened)
%an / %ae / %ad / %ar — Author name, email, date (relative)
%cd / %ce / %cd / %cr — Committer name, email, date (relative)
%n — newline

Date format can be specific (1961-01-13), or relative ("4 years 23 months"). Can replace spaces with dots: 4.years.23.months. The actual format is undocumented (OF COURSE), but you can look at the approxidate code.

Three faces of git diff (git->General)

Fri, 04 May 2012 19:29:50 UTC

git diff shows changes made since the file was last staged. If you make changes, stage them, then make more changes, this only shows you the more changes

git diff --staged shows changes made to the file when it was staged, diffs against the committed version it's based off of. It doesn't include any changes you've made since staging.

git diff HEAD (where HEAD is the name of a commit - HEAD to compare with the latest commit, or a branch name to compare to the tip of that branch. In essence, unions git diff and git diff HEAD

Password-less github gitting (git->General)

Fri, 04 May 2012 17:25:05 UTC

Typing in your username and password for github is annoying. You'll need to do the ssh key dance. instructions here.

If your current checkout is via https (you can figure that out by doing git config -l (ell) and looking at the remote.origin.url. If it's https you're not going to use your ssh keys. You'll need to change it.

If it was originally:

remote.origin.url=https://github.com/someuser/GroovyProject.git

You'd do:

% git config remote.origin.url git@github.com:someuser/GroovyProject.git

git "revert" (git->General)

Mon, 23 Apr 2012 19:16:50 UTC

To remove uncommitted changes so you can pull without complaint (revert in svn-speak):

% git checkout  filename-to-revert

This checks the file out from HEAD, removing the local modificaiton. (put -- before the file name in case you have a branch named the same as the file)

Seeing entitlement and certification information (Provisioning Hell->Hacks)

Fri, 13 Apr 2012 22:14:11 UTC

Sometimes it's useful to see what certificate was used for signing, and what entitlements are in your app. The codesign tool does that.

How to use:

% cd ~/Library/Developer/Xcode/Archives/$DATE/Campwhere.xcarchive/Products/Applications
% codesign -dvvv codesign -dvvv ./Campwhere.app
% codesign -d --entitlements - ./Campwhere.app

Describe table in sqlite3 (sqlite3->General)

Thu, 12 Apr 2012 16:06:50 UTC

To see the table structure, use .schema

sqlite> .schema camp
CREATE TABLE camp (code INTEGER, label TEXT, state TEXT, type TEXT, phone TEXT, sites INTEGER, nforg TEXT, lat NUMERIC, lon NUMERIC, elevation NUMERIC, fee TEXT);
CREATE INDEX pkdex ON camp (code);

Basic NSURLConnection delegate methods (NSURL->General)

Fri, 06 Apr 2012 18:13:29 UTC



- (void) connection: (NSURLConnection *) connection
 didReceiveResponse: (NSURLResponse *) response;

- (void) connection:  (NSURLConnection *) connection  didReceiveData: (NSData *) data;

- (void) connection: (NSURLConnection *) connection  didFailWithError: (NSError *) error;

- (void) connectionDidFinishLoading: (NSURLConnection *) connection;

Only allowing numbers in a text field (UITextField->General)

Thu, 05 Apr 2012 01:09:03 UTC

Sometimes you need a more general keyboard for a numeric-only text field. You can do something like this in a delegate method:

- (BOOL) textField: (UITextField *) textField
  shouldChangeCharactersInRange: (NSRange) range
              replacementString: (NSString *) string {
    NSString *resultingString = [textField.text stringByReplacingCharactersInRange: range
                                          withString: string];
    if (resultingString.length == 0) return YES;
    NSScanner *scanner = [NSScanner scannerWithString: resultingString];

    float throwaway;
    BOOL scansFloat = [scanner scanFloat: &throwaway];
    BOOL atEnd = [scanner isAtEnd];

    return scansFloat && atEnd;

} // shouldChangedCharacersInRanges

(thanks to Frank Shearer, from a SO post)

Getting notified of UITextField changes (UITextField->General)

Wed, 04 Apr 2012 23:00:48 UTC

Easiest way is to hook up the Editing Changed (NOT Value Changed) action.

Rsyncing a directory hierarchy from one machine to another (Unix->General)

Wed, 07 Mar 2012 21:28:43 UTC

I'm moving a bunch of movie files from one machine to another. I used this rsync command to copy it from the remote machine to the local one to the directory /Volumes/Media2

% rsync -avz -e ssh --progress 'biggun.local:/Volumes/Video/AppleTV\ Videos/Exercise' /Volumes/Media2

I can never remember what the flags mean, so:

-a : archive mode (recursive, also preserve symlinks, permissions, owner and group)
-v : verbose
-z : compress for transport
-e ssh : use ssh for the transport pipeline
--progress : see progress info

Preventing an app from opening stale windows (Unix->General)

Tue, 06 Mar 2012 16:37:53 UTC

Lion introduced the idea that apps restore all their windows that were last open. Sometimes that's wonderful. For some apps, it's maddening. You can tweak individual apps by setting a default:

% defaults write com.bignerdranch.bigshow NSQuitAlwaysKeepsWindows -bool false

(thanks to Step Christopher for this one)

Block that measures time. (Tools->General)

Sun, 26 Feb 2012 21:59:04 UTC

Sometimes you want to do a quick measurement of a chunk of code to see how long it takes, and you don't want to crank up ~~gprof~~ ~~Shark~~ Instruments to do it. mach_absolute_time is the finest-grained timer in the system. Here's a little utility to time a block:


#import <mach/mach_time.h>  // for mach_absolute_time() and friends

CGFloat BWTimeBlock (void (^block)(void)) {
    mach_timebase_info_data_t info;
    if (mach_timebase_info (&info) != KERN_SUCCESS) return -1;

    uint64_t start = mach_absolute_time ();
    block ();
    uint64_t end = mach_absolute_time ();
    uint64_t elapsed = end - start;

    uint64_t nanos = elapsed * info.numer / info.denom;
    return (CGFloat)nanos / NSEC_PER_SEC;

} // BWTimeBlock

And you would use it like:

    NSString *thing1 = @"hi";
    NSString *thing2 = @"hello there";

    time = BWTimeBlock(^{
            for (int i = 0; i < LOOPAGE; i++) {
                [thing1 isEqualTo: thing2];
            }
        });
    printf ("equalTo time: %f\n", time);

Turn off the Lion "autorepeat shows accent chooser" (General->General)

Thu, 09 Feb 2012 22:50:45 UTC

I actually want my characters to autorepeat rather than seeing the accent chooser. Run this in the terminal, and restart affected apps:

defaults write -g ApplePressAndHoldEnabled -bool false

(thanks to Paul Kafasis)

Triggering a low-memory warning on the device (Debugging->General)

Fri, 03 Feb 2012 19:34:35 UTC

You can trigger a low-memory warning in the simulator, but sometimes you use one of the myriad of APIs that aren't supported in the simulator, but you still need to track down something ultimately triggered by a low-memory warning.

Put this somewhere convenient to trigger - in a timer, under a button, or something. Obviously, you don't want to ship with it.

[[UIApplication sharedApplication] performSelector: @selector(_performMemoryWarning)];

Using a nib for a tableview cell (UITableView->General)

Sat, 28 Jan 2012 02:01:55 UTC

You can use a nib file for table view cells pretty easily in iOS5.

1) Make a nib with a single object at the top, a UITableViewCell. Lay it out as you wish. I use view tags to get to the objects contained therein.

enum {
    kTermLabelTag = 1,
    kDetailLabelTag = 2
};

2) Register the nib for a cell reuse identifier. I do it in my -viewDidLoad.

static NSString *g_cellReuseIdentifier = @"BWLookupCellReuseIdentifier"; // file global

...

    UINib *nib = [UINib nibWithNibName: @"BWLookupTableViewCell"  bundle: nil];
    [self.resultsView registerNib: nib
         forCellReuseIdentifier: g_cellReuseIdentifier];

3) Dequeue the cell as usual

    UITableViewCell *cell =
        [tableView dequeueReusableCellWithIdentifier: g_cellReuseIdentifier];

    if (!cell) {
        cell = [[UITableViewCell alloc]
                   initWithStyle: UITableViewCellStyleSubtitle
                   reuseIdentifier: g_cellReuseIdentifier];
    }

4) Dig into the cell with the tags, and go nuts

    UILabel *termLabel = (UILabel *)[cell viewWithTag: kTermLabelTag];
    UILabel *detailLabel = (UILabel *)[cell viewWithTag: kDetailLabelTag];

    termLabel.text = termString;
    detailLabel.text = definition;

Converting degrees to radians and back (Graphics->General)

Thu, 29 Dec 2011 23:31:44 UTC

Most programming interfaces that deal with angles talk in radians (2 pi radians in a circle), like CGAffineTransformRotate. I personally think better in degrees (360 degrees in a circle).

Convert degrees to radians by multiplying by 180 / pi.

Convert radians to degrees by multiplying by pi / 180

I have a couple of #defines I stick into a common header for projects that need it;

#define BWDegToRad(d)   ((d) * M_PI / 180.0)
#define BWRadToDeg(r)   ((r) * 180 / M_PI)

Push/pop CGContext state (Graphics->General)

Thu, 29 Dec 2011 02:56:29 UTC

CGContextRef context = ...;

...
CGContextSaveGState (context); {
    [drawable drawWithContext: context
              inRect: bounds
              withMetrics: self.metrics]; // or whatever drawing you're doing
} CGContextRestoreGState (context);

Edit: Gus Meuller of Flying Meat fame has a block-based utility that does this:

void FMCGContextHoldGState (CGContextRef context, void (^block)()) {
    CGContextSaveGState(context); {
        block ();
    } CGContextRestoreGState(context);
}

and if you're wanting to do something similar with NSGraphicsContexts:

void FMNSContextHoldGState (void (^block)()) {
    [NSGraphicsContext saveGraphicsState]; {
        block ();
    } [NSGraphicsContext restoreGraphicsState];
}

Sort case-insensitive (emacs->General)

Mon, 26 Dec 2011 03:42:07 UTC

M-x sort-lines uses a case-sensitive search. When that sucks, you can tell emacs to be case insensitive (globally) by doing M-x set-variable RET sort-fold-case RET t

UITableView section header titles (UITableView->General)

Mon, 26 Dec 2011 01:45:23 UTC

UITableView won't display its groovy section headers (or footers) until you supply them via the datasource:

- (NSString *) tableView: (UITableView *) tableview
 titleForHeaderInSection: (NSInteger) section {
    NSArray *sections = [BWTermStorage sections];
    return [sections objectAtIndex: section];
} // titleForHeaderInSection

You can return a title for a footer.

You can also return a view:

- (UIView *) tableView: (UITableView *) tableView 
    viewForHeaderInSection: (NSInteger) section;