Correctly locate common proto files

.gitignore

@@ -8,3 +8,4 @@ system-test/secrets.js
 system-test/*key.json
 *.lock
 *-lock.js*
+google/

.jsdoc.js

@@ -23,23 +23,19 @@ module.exports = {
     template: './node_modules/ink-docstrap/template',
     recurse: true,
     verbose: true,
-    destination: './docs/'
+    destination: './docs/',
   },
-  plugins: [
-    'plugins/markdown'
-  ],
+  plugins: ['plugins/markdown'],
   source: {
     excludePattern: '(^|\\/|\\\\)[._]',
-    include: [
-      'src'
-    ],
-    includePattern: '\\.js$'
+    include: ['src'],
+    includePattern: '\\.js$',
   },
   templates: {
     copyright: 'Copyright 2017 Google, Inc.',
     includeDate: false,
     sourceFiles: false,
     systemName: 'google-proto-files',
-    theme: 'lumen'
-  }
+    theme: 'lumen',
+  },
 };

load.js

@@ -4,39 +4,60 @@ var globby = require('globby');
 var path = require('path');
 var protobuf = require('protobufjs');
 
-var COMMON_PROTO_DIRS = [
-  // This list of directories is defined here:
-  // https://github.com/googleapis/googleapis/blob/master/gapic/packaging/common_protos.yaml
-  'api',
-  path.join('logging', 'type'),
-  'longrunning',
-  'protobuf', // This is an additional path that the common protos depend on.
-  'rpc',
-  'type',
-];
-
-var COMMON_PROTO_GLOB_PATTERNS = COMMON_PROTO_DIRS.map(function(dir) {
-  return path.join('google', dir, '**', '*.proto');
-});
-
-var COMMON_PROTO_FILES = globby.sync(COMMON_PROTO_GLOB_PATTERNS);
+let COMMON_PROTO_FILES;
 
 class GoogleProtoFilesRoot extends protobuf.Root {
   constructor() {
     super([].slice.apply(arguments));
   }
 
+  // Caches and returns an array of the local common/google core proto files
+  // exist on disk.
+  static getCommonProtoFiles() {
+    var commonProtoDirs = [
+      // This list of directories is defined here:
+      // https://github.com/googleapis/googleapis/blob/master/gapic/packaging/common_protos.yaml
+      'api',
+      path.join('logging', 'type'),
+      'longrunning',
+      'protobuf', // This is an additional path that the common protos depend on.
+      'rpc',
+      'type',
+    ];
+
+    var commonProtoGlobPatterns = commonProtoDirs.map(dir =>
+      path.join(__dirname, 'google', dir, '**', '*.proto')
+    );
+
+    if (!COMMON_PROTO_FILES) {
+      COMMON_PROTO_FILES = globby
+        .sync(commonProtoGlobPatterns)
+        .map(path.normalize);
+    }
+
+    return COMMON_PROTO_FILES;
+  }
+
   // Causes the loading of an included proto to check if it is a common
   // proto. If it is a common proto, use the google-proto-files proto.
   resolvePath(_, includePath) {
+    includePath = path.normalize(includePath);
+
     // Fully qualified paths don't need to be resolved.
-    if (includePath.startsWith('/')) {
+    if (path.isAbsolute(includePath)) {
       return includePath;
     }
 
-    if (COMMON_PROTO_FILES.indexOf(includePath) > -1) {
-      return path.join(__dirname, includePath);
+    const fullIncludePath = path.join(
+      __dirname,
+      path.relative(__dirname, includePath)
+    );
+    const commonProtoFiles = GoogleProtoFilesRoot.getCommonProtoFiles();
+
+    if (commonProtoFiles.indexOf(fullIncludePath) > -1) {
+      return fullIncludePath;
     }
+
     return protobuf.util.path.resolve.apply(null, [].slice.call(arguments));
   }
 }