Possible memory leak in ui.ImageView

[rebryant]

I am trying to create animations by displaying a sequence of JPG images. My code consistently crashes Pythonista after a few hundred images. By "crash" I mean that Pythonista silently exits, and when restarting the app, the console session is empty.

I suspect that there's a memory leak. When replacing the ImageView image, the old one doesn't get dereferenced, and so the app runs out of memory.

Here's some code that demonstrates the problem:

---

import ui
import urllib

class GUI:
    mainView = None
    imageView = None
    images = ['im1.jpg', 'im2.jpg', 'im3.jpg']
    afile = "log.txt"
    url = "http://www.cs.cmu.edu/~bryant/"

    def __init__(self):
        iwidth = 2048
	iheight = 1536
        width = iwidth/4
        height = iheight/4
        self.mainView = ui.View(frame=(0,0,width,height))
        self.imageView = ui.ImageView(frame=(0,0,width,height))
	self.imageView.center = (width/2,height/2)
        self.mainView.add_subview(self.imageView)
        self.mainView.present('sheet')
        self.download()

    def download(self):
        for iname in self.images:
            url = self.url + iname
            urllib.urlretrieve(url, iname)
            print "Downloaded %s" % url

    def archive(self, msg):
        print msg
        f = open(self.afile, "a")
        f.write(msg + "\n")
        f.close()

    def run(self):
        for count in xrange(2000):
            iname = self.images[count % len(self.images)]
            imx = ui.Image.named(iname)
            self.archive("Showing image #%d %s" % (count, iname))
            self.imageView.image = imx
        self.mainView.close()

gui = GUI()
gui.run()

---

[Dutcho]

Reproduced (on iPad, Python 3, latest beta, latest iOS) after more than 1,000 images when trying to process the photos library by below minimal snippet:

import photos
for i, p in enumerate(photos.get_assets()):
    print(i, end=' ')
    image = p.get_image()
    # process image in whatever way; omitted here for clarity
    del image

Changing get_image() into get_image_data() in above snippet:

1. significantly sped up the process (generating the sequence of i's);
2. terminated with a MemoryError caused by a SystemError in method seek of _io.BytesIO that returned with an error set after 1,363 images.

Assuming get_image() builds on get_image_data() (it did for functions in library module photos.py, line 86, so the same may well apply for Asset methods in _photos2), that would suggest:

• get_image() doesn't properly handle some error condition flagged by get_image_data();
• get_image_data() is the cause of the memory leak.

[zrzka]

Still reproducible in 311014 on iPad Pro. Crashes after 1847 images ...