Only calculate slave->build mapping once in json output.

third_party/buildbot_8_4p1/buildbot/status/web/status_json.py

 # This file is part of Buildbot.  Buildbot is free software: you can
 # redistribute it and/or modify it under the terms of the GNU General Public
 # License as published by the Free Software Foundation, version 2.
 #
 # This program is distributed in the hope that it will be useful, but WITHOUT
 # ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 # FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
 # details.
 #
 # You should have received a copy of the GNU General Public License along with
 # this program; if not, write to the Free Software Foundation, Inc., 51
 # Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 #
 # Portions Copyright Buildbot Team Members
 # Original Copyright (c) 2010 The Chromium Authors.
 
 """Simple JSON exporter."""
 
+import collections
 import datetime
 import os
 import re
 
 from twisted.internet import defer
 from twisted.web import html, resource, server
 
 from buildbot.status.web.base import HtmlResource
 from buildbot.util import json
 
@@ skipping 599 matching lines @@
 
     def getBuilders(self):
         if self.builders is None:
             # Figure out all the builders to which it's attached
             self.builders = []
             for builderName in self.status.getBuilderNames():
                 if self.name in self.status.getBuilder(builderName).slavenames:
                     self.builders.append(builderName)
         return self.builders
 
+    def getSlaveBuildMap(self, buildcache, buildercache):
+        for builderName in self.getBuilders():
+            if builderName not in buildercache:
+                buildercache.add(builderName)
+                builder_status = self.status.getBuilder(builderName)
+                for i in range(1, builder_status.buildCacheSize - 1):
+                    build_status = builder_status.getBuild(-i)
+                    if not build_status or not build_status.isFinished():
+                        # If not finished, it will appear in runningBuilds.
+                        break
+                    slave = buildcache[build_status.getSlavename()]
+                    slave.setdefault(builderName, []).append(
+                            build_status.getNumber())
+        return buildcache[self.name]
+
     def asDict(self, request):
+        if not hasattr(request, 'custom_data'):
+            request.custom_data = {}
+        if 'buildcache' not in request.custom_data:
+            # buildcache is used to cache build information across multiple
+            # invocations of SlaveJsonResource. It should be set to an empty
+            # collections.defaultdict(dict).
+            request.custom_data['buildcache'] = collections.defaultdict(dict)
+
+            # Tracks which builders have been stored in the buildcache.
+            request.custom_data['buildercache'] = set()
+
         results = self.slave_status.asDict()
-        # Enhance it by adding more informations.
-        results['builders'] = {}
-        for builderName in self.getBuilders():
-            builds = []
-            builder_status = self.status.getBuilder(builderName)
-            for i in range(1, builder_status.buildCacheSize - 1):
-                build_status = builder_status.getBuild(-i)
-                if not build_status or not build_status.isFinished():
-                    # If not finished, it will appear in runningBuilds.
-                    break
-                if build_status.getSlavename() == self.name:
-                    builds.append(build_status.getNumber())
-            results['builders'][builderName] = builds
+        # Enhance it by adding more information.
+        results['builders'] = self.getSlaveBuildMap(
+                request.custom_data['buildcache'],
+                request.custom_data['buildercache'])
         return results
 
 
 class SlavesJsonResource(JsonResource):
     help = """List the registered slaves.
 """
     pageTitle = 'Slaves'
 
     def __init__(self, status):
         JsonResource.__init__(self, status)
@@ skipping 75 matching lines @@
         if not builder:
             return
         EXAMPLES = EXAMPLES.replace('<A_BUILDER>', builder.getName())
         build = builder.getBuild(-1)
         if build:
             EXAMPLES = EXAMPLES.replace('<A_BUILD>', str(build.getNumber()))
         if builder.slavenames:
             EXAMPLES = EXAMPLES.replace('<A_SLAVE>', builder.slavenames[0])
 
 # vim: set ts=4 sts=4 sw=4 et: