Improve cache logic for lookup operations

platformio/pkgmanager.py

@@ -8,28 +8,24 @@ from time import time
 
 import click
 
-from platformio import exception, telemetry
+from platformio import exception, telemetry, util
 from platformio.app import get_state_item, set_state_item
 from platformio.downloader import FileDownloader
 from platformio.unpacker import FileUnpacker
-from platformio.util import get_api_result, get_home_dir, get_systype
 
 
 class PackageManager(object):
 
     def __init__(self):
-        self._package_dir = join(get_home_dir(), "packages")
+        self._package_dir = join(util.get_home_dir(), "packages")
         if not isdir(self._package_dir):
             makedirs(self._package_dir)
         assert isdir(self._package_dir)
 
     @classmethod
+    @util.memoized
     def get_manifest(cls):
-        try:
+        return util.get_api_result("/packages/manifest")
-            return cls._cached_manifest
-        except AttributeError:
-            cls._cached_manifest = get_api_result("/packages/manifest")
-        return cls._cached_manifest
 
     @staticmethod
     def download(url, dest_dir, sha1=None):
@@ -63,7 +59,7 @@ class PackageManager(object):
             raise exception.UnknownPackage(name)
 
         # check system platform
-        systype = get_systype()
+        systype = util.get_systype()
         builds = ([b for b in manifest[name] if b['system'] == "all" or systype
                    in b['system']])
         if not builds:

platformio/platforms/base.py

@@ -132,12 +132,9 @@ class PlatformFactory(object):
         return module
 
     @classmethod
-    def get_platforms(cls, installed=False):
+    @util.memoized
+    def _lookup_platforms(cls):
         platforms = {}
-
-        try:
-            platforms = cls.get_platforms_cache
-        except AttributeError:
         for d in (util.get_home_dir(), util.get_source_dir()):
             pdir = join(d, "platforms")
             if not isdir(pdir):
@@ -157,7 +154,11 @@ class PlatformFactory(object):
                         platforms[type_] = path
                 except exception.UnknownPlatform:
                     pass
-            cls.get_platforms_cache = platforms
+        return platforms
+
+    @classmethod
+    def get_platforms(cls, installed=False):
+        platforms = cls._lookup_platforms()
 
         if not installed:
             return platforms

platformio/util.py

@@ -1,6 +1,8 @@
 # Copyright (C) Ivan Kravets <me@ikravets.com>
 # See LICENSE for details.
 
+import collections
+import functools
 import json
 import os
 import re
@@ -53,6 +55,39 @@ class AsyncPipe(Thread):
         self.join()
 
 
+class memoized(object):
+    '''
+    Decorator. Caches a function's return value each time it is called.
+    If called later with the same arguments, the cached value is returned
+    (not reevaluated).
+    https://wiki.python.org/moin/PythonDecoratorLibrary#Memoize
+    '''
+
+    def __init__(self, func):
+        self.func = func
+        self.cache = {}
+
+    def __call__(self, *args):
+        if not isinstance(args, collections.Hashable):
+            # uncacheable. a list, for instance.
+            # better to not cache than blow up.
+            return self.func(*args)
+        if args in self.cache:
+            return self.cache[args]
+        else:
+            value = self.func(*args)
+            self.cache[args] = value
+            return value
+
+    def __repr__(self):
+        '''Return the function's docstring.'''
+        return self.func.__doc__
+
+    def __get__(self, obj, objtype):
+        '''Support instance methods.'''
+        return functools.partial(self.__call__, obj)
+
+
 def get_systype():
     data = uname()
     return ("%s_%s" % (data[0], data[4])).lower()
@@ -239,11 +274,9 @@ def get_api_result(path, params=None, data=None):
     return result
 
 
-def get_boards(type_=None):
+@memoized
+def _lookup_boards():
     boards = {}
-    try:
-        boards = get_boards._cache  # pylint: disable=W0212
-    except AttributeError:
     bdirs = [join(get_source_dir(), "boards")]
     if isdir(join(get_home_dir(), "boards")):
         bdirs.append(join(get_home_dir(), "boards"))
@@ -254,7 +287,11 @@ def get_boards(type_=None):
                 continue
             with open(join(bdir, json_file)) as f:
                 boards.update(json.load(f))
-        get_boards._cache = boards  # pylint: disable=W0212
+    return boards
+
+
+def get_boards(type_=None):
+    boards = _lookup_boards()
 
     if type_ is None:
         return boards
@@ -264,12 +301,9 @@ def get_boards(type_=None):
         return boards[type_]
 
 
-def get_frameworks(type_=None):
+@memoized
+def _lookup_frameworks():
     frameworks = {}
-
-    try:
-        frameworks = get_frameworks._cache  # pylint: disable=W0212
-    except AttributeError:
     frameworks_path = join(
         get_source_dir(), "builder", "scripts", "frameworks")
 
@@ -290,7 +324,11 @@ def get_frameworks(type_=None):
                 "url": doclines[-1],
                 "script": script_path
             }
-        get_frameworks._cache = frameworks  # pylint: disable=W0212
+    return frameworks
+
+
+def get_frameworks(type_=None):
+    frameworks = _lookup_frameworks()
 
     if type_ is None:
         return frameworks