textures: fix texturepath option not being used

If the first texture loaded was not in the pack, i.e. we fell back
on system textures, then the pack was ignored altogether for the
remainder of the render.

Here we fix this by using an OrderedDict instead of the split jars
and jarpath nonsense, and then always checking the custom textures
first and opening them if they are not already open, and putting
the jar file handle at the start of the OrderedDict.

We also switch around some logic to avoid unnecessary isdir calls
when we're using a resource pack.

overviewer_core/textures.py

@@ -13,6 +13,7 @@
 #    You should have received a copy of the GNU General Public License along
 #    with the Overviewer.  If not, see <http://www.gnu.org/licenses/>.
 
+from collections import OrderedDict
 import sys
 import imp
 import os
@@ -86,8 +87,7 @@ class Textures(object):
         self.texture_cache = {}
 
         # once we find a jarfile that contains a texture, we cache the ZipFile object here
-        self.jars = []
-        self.jarpaths = []
+        self.jars = OrderedDict()
     
     ##
     ## pickle support
@@ -101,7 +101,7 @@ class Textures(object):
                 del attributes[attr]
             except KeyError:
                 pass
-        attributes['jars'] = []
+        attributes['jars'] = OrderedDict()
         return attributes
     def __setstate__(self, attrs):
         # regenerate textures, if needed
@@ -162,8 +162,8 @@ class Textures(object):
         """Searches for the given file and returns an open handle to it.
         This searches the following locations in this order:
         
+        * In the directory textures_path given in the initializer if not already open
         * In an already open resource pack or client jar file
-        * In the directory textures_path given in the initializer
         * In the resource pack given by textures_path
         * The program dir (same dir as overviewer.py) for extracted textures
         * On Darwin, in /Applications/Minecraft for extracted textures
@@ -182,31 +182,11 @@ class Textures(object):
         """
         if verbose: logging.info("Starting search for {0}".format(filename))
 
-        # we've sucessfully loaded something from here before, so let's quickly try
-        # this before searching again
-        # We might already know some jarpaths from other processes though.
-        if len(self.jarpaths) > len(self.jars):
-            for p in self.jarpaths:
-                self.jars.append(zipfile.ZipFile(p))
-        if len(self.jars) > 0:
-            for jar_num, jar in enumerate(self.jars):
-                try:
-                    jar.getinfo(filename)
-                    if verbose: logging.info("Found (cached) %s in '%s'", filename,
-                                             self.jarpaths[jar_num])
-                    return jar.open(filename)
-                except (KeyError, IOError) as e:
-                    pass
-
         # A texture path was given on the command line. Search this location
         # for the file first.
         if self.find_file_local_path:
-            if os.path.isdir(self.find_file_local_path):
-                full_path = os.path.join(self.find_file_local_path, filename)
-                if os.path.isfile(full_path):
-                        if verbose: logging.info("Found %s in '%s'", filename, full_path)
-                        return open(full_path, mode)
-            elif os.path.isfile(self.find_file_local_path):
+            if (self.find_file_local_path not in self.jars
+                and os.path.isfile(self.find_file_local_path)):
                 # Must be a resource pack. Look for the requested file within
                 # it.
                 try:
@@ -216,11 +196,29 @@ class Textures(object):
                     pack.getinfo(filename)
                     if verbose: logging.info("Found %s in '%s'", filename,
                                              self.find_file_local_path)
-                    self.jars.append(pack)
-                    self.jarpaths.append(self.find_file_local_path)
+                    self.jars[self.find_file_local_path] = pack
+                    # ok cool now move this to the start so we pick it first
+                    self.jars.move_to_end(self.find_file_local_path, last=False)
                     return pack.open(filename)
                 except (zipfile.BadZipfile, KeyError, IOError):
                     pass
+            elif os.path.isdir(self.find_file_local_path):
+                full_path = os.path.join(self.find_file_local_path, filename)
+                if os.path.isfile(full_path):
+                        if verbose: logging.info("Found %s in '%s'", filename, full_path)
+                        return open(full_path, mode)
+
+        # We already have some jars open, better use them.
+        if len(self.jars) > 0:
+            for jarpath in self.jars:
+                try:
+                    jar = self.jars[jarpath]
+                    jar.getinfo(filename)
+                    if verbose: logging.info("Found (cached) %s in '%s'", filename,
+                                             jarpath)
+                    return jar.open(filename)
+                except (KeyError, IOError) as e:
+                    pass
 
         # If we haven't returned at this point, then the requested file was NOT
         # found in the user-specified texture path or resource pack.
@@ -301,8 +299,7 @@ class Textures(object):
                 try:
                     jar.getinfo(filename)
                     if verbose: logging.info("Found %s in '%s'", filename, jarpath)
-                    self.jars.append(jar)
-                    self.jarpaths.append(jarpath)
+                    self.jars[jarpath] = jar
                     return jar.open(filename)
                 except (KeyError, IOError) as e:
                     pass