Cache icon data

On Unix there is no problem in saving the pixmap and opening the file immediately after
to read its content. On Windows, however, the file is always half-written so we get
corrupted data. Cache the icon binary representation and use it in get_image instead
of opening and reading the file directly.

blink/resources.py

@@ -9,11 +9,15 @@ import os
 import platform
 import sys
 
-from PyQt4.QtCore import Qt
-from PyQt4.QtGui  import QIcon, QPixmap
+from PyQt4.QtCore import Qt, QBuffer, QThread
+from PyQt4.QtGui  import QApplication, QIcon, QPixmap
+
 from application.python.descriptor import classproperty
 from application.python.types import Singleton
 from application.system import makedirs, unlink
+from threading import Event
+
+from blink.util import run_in_gui_thread
 
 
 class DirectoryContextManager(unicode):
@@ -88,21 +92,38 @@ class IconManager(object):
         except KeyError:
             pixmap = QPixmap()
             filename = ApplicationData.get(os.path.join('images', id + '.png'))
-            if pixmap.load(filename):
+            try:
+                data = file(filename).read()
+            except (IOError, OSError):
+                data = None
+            if pixmap.loadFromData(data):
                 icon = QIcon(pixmap)
                 icon.filename = filename
+                icon.content = data
             else:
                 icon = None
             return self.iconmap.setdefault(id, icon)
 
     def get_image(self, id):
-        icon = self.get(id)
+        application = QApplication.instance()
+        if QThread.currentThread() is application.thread():
+            icon = self.get(id)
+        else:
+            @run_in_gui_thread
+            def get_icon(id, event):
+                try:
+                    event.icon = self.get(id)
+                except:
+                    event.icon = None
+                finally:
+                    event.set()
+            event = Event()
+            get_icon(id, event)
+            event.wait()
+            icon = event.icon
         if icon is None:
             return None
-        try:
-            return file(icon.filename).read()
-        except Exception:
-            return None
+        return icon.content
 
     def store_data(self, id, data):
         directory = ApplicationData.get('images')
@@ -112,9 +133,14 @@ class IconManager(object):
         if data is not None and pixmap.loadFromData(data):
             if pixmap.size().width() > self.max_size or pixmap.size().height() > self.max_size:
                 pixmap = pixmap.scaled(self.max_size, self.max_size, Qt.KeepAspectRatio, Qt.SmoothTransformation)
-            pixmap.save(filename)
+            buffer = QBuffer()
+            pixmap.save(buffer, 'png')
+            data = str(buffer.data())
+            with open(filename, 'wb') as f:
+                f.write(data)
             icon = QIcon(pixmap)
             icon.filename = filename
+            icon.content = data
         else:
             unlink(filename)
             icon = None
@@ -131,9 +157,14 @@ class IconManager(object):
         if file is not None and pixmap.load(file):
             if pixmap.size().width() > self.max_size or pixmap.size().height() > self.max_size:
                 pixmap = pixmap.scaled(self.max_size, self.max_size, Qt.KeepAspectRatio, Qt.SmoothTransformation)
-            pixmap.save(filename)
+            buffer = QBuffer()
+            pixmap.save(buffer, 'png')
+            data = str(buffer.data())
+            with open(filename, 'wb') as f:
+                f.write(data)
             icon = QIcon(pixmap)
             icon.filename = filename
+            icon.content = data
         else:
             unlink(filename)
             icon = None