1 files changed, 118 insertions, 0 deletions
diff --git a/devtools/shared/platform/cache-entry.js b/devtools/shared/platform/cache-entry.js
new file mode 100644
index 0000000000..7efd460ad8
--- /dev/null
+++ b/devtools/shared/platform/cache-entry.js
@@ -0,0 +1,118 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+"use strict";
+
+const Services = require("Services");
+const { Ci } = require("chrome");
+loader.lazyRequireGetter(
+  this,
+  "NetworkHelper",
+  "devtools/shared/webconsole/network-helper"
+);
+
+/**
+ * Module to fetch cache objects from CacheStorageService
+ * and return them as an object.
+ */
+exports.CacheEntry = {
+  /**
+   * Flag for cache session being initialized.
+   */
+  isCacheSessionInitialized: false,
+  /**
+   * Cache session object.
+   */
+  cacheSession: null,
+
+  /**
+   * Initializes our cache session / cache storage session.
+   */
+  initializeCacheSession: function(request) {
+    try {
+      const cacheService = Services.cache2;
+      if (cacheService) {
+        let loadContext = NetworkHelper.getRequestLoadContext(request);
+        if (!loadContext) {
+          // Get default load context if we can't fetch.
+          loadContext = Services.loadContextInfo.default;
+        }
+        this.cacheSession = cacheService.diskCacheStorage(loadContext, false);
+        this.isCacheSessionInitialized = true;
+      }
+    } catch (e) {
+      this.isCacheSessionInitialized = false;
+    }
+  },
+
+  /**
+   * Parses a cache descriptor returned from the backend into a
+   * usable object.
+   *
+   * @param Object descriptor The descriptor from the backend.
+   */
+  parseCacheDescriptor: function(descriptor) {
+    const descriptorObj = {};
+    try {
+      if (descriptor.storageDataSize) {
+        descriptorObj.dataSize = descriptor.storageDataSize;
+      }
+    } catch (e) {
+      // We just need to handle this in case it's a js file of 0B.
+    }
+    if (descriptor.expirationTime) {
+      descriptorObj.expires = descriptor.expirationTime;
+    }
+    if (descriptor.fetchCount) {
+      descriptorObj.fetchCount = descriptor.fetchCount;
+    }
+    if (descriptor.lastFetched) {
+      descriptorObj.lastFetched = descriptor.lastFetched;
+    }
+    if (descriptor.lastModified) {
+      descriptorObj.lastModified = descriptor.lastModified;
+    }
+    if (descriptor.deviceID) {
+      descriptorObj.device = descriptor.deviceID;
+    }
+    return descriptorObj;
+  },
+
+  /**
+   * Does the fetch for the cache descriptor from the session.
+   *
+   * @param string request
+   *        The request object.
+   * @param Function onCacheDescriptorAvailable
+   *        callback function.
+   */
+  getCacheEntry: function(request, onCacheDescriptorAvailable) {
+    if (!this.isCacheSessionInitialized) {
+      this.initializeCacheSession(request);
+    }
+    if (this.cacheSession) {
+      const uri = NetworkHelper.nsIURL(request.URI.spec);
+      this.cacheSession.asyncOpenURI(
+        uri,
+        "",
+        Ci.nsICacheStorage.OPEN_SECRETLY,
+        {
+          onCacheEntryCheck: (entry, appcache) => {
+            return Ci.nsICacheEntryOpenCallback.ENTRY_WANTED;
+          },
+          onCacheEntryAvailable: (descriptor, isnew, appcache, status) => {
+            if (descriptor) {
+              const descriptorObj = this.parseCacheDescriptor(descriptor);
+              onCacheDescriptorAvailable(descriptorObj);
+            } else {
+              onCacheDescriptorAvailable(null);
+            }
+          },
+        }
+      );
+    } else {
+      onCacheDescriptorAvailable(null);
+    }
+  },
+};