[Files app] ES6 class for multi_metadata_provider.js

Bug: 778674
Change-Id: Ib270ab8c6f7ddc916d724ae8e0d64bbce22031ba
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1647643
Commit-Queue: François Degros <fdegros@chromium.org>
Commit-Queue: Luciano Pacheco <lucmult@chromium.org>
Auto-Submit: François Degros <fdegros@chromium.org>
Reviewed-by: Luciano Pacheco <lucmult@chromium.org>
Cr-Commit-Position: refs/heads/master@{#666618}

ui/file_manager/file_manager/foreground/js/metadata/multi_metadata_provider.js

@@ -2,50 +2,175 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-/**
- * @param {!FileSystemMetadataProvider} fileSystemMetadataProvider
- * @param {!ExternalMetadataProvider} externalMetadataProvider
- * @param {!ContentMetadataProvider} contentMetadataProvider
- * @param {!VolumeManager} volumeManager
- * @constructor
- * @extends {MetadataProvider}
- * @struct
- */
-function MultiMetadataProvider(
-    fileSystemMetadataProvider, externalMetadataProvider,
-    contentMetadataProvider, volumeManager) {
-  MetadataProvider.call(
-      this,
-      FileSystemMetadataProvider.PROPERTY_NAMES
-          .concat(ExternalMetadataProvider.PROPERTY_NAMES)
-          .concat(ContentMetadataProvider.PROPERTY_NAMES));
-
+/** @final */
+class MultiMetadataProvider extends MetadataProvider {
   /**
-   * @private {!FileSystemMetadataProvider}
-   * @const
+   * @param {!FileSystemMetadataProvider} fileSystemMetadataProvider
+   * @param {!ExternalMetadataProvider} externalMetadataProvider
+   * @param {!ContentMetadataProvider} contentMetadataProvider
+   * @param {!VolumeManager} volumeManager
    */
-  this.fileSystemMetadataProvider_ = fileSystemMetadataProvider;
+  constructor(
+      fileSystemMetadataProvider, externalMetadataProvider,
+      contentMetadataProvider, volumeManager) {
+    super(FileSystemMetadataProvider.PROPERTY_NAMES
+              .concat(ExternalMetadataProvider.PROPERTY_NAMES)
+              .concat(ContentMetadataProvider.PROPERTY_NAMES));
 
-  /**
-   * @private {!ExternalMetadataProvider}
-   * @const
-   */
-  this.externalMetadataProvider_ = externalMetadataProvider;
+    /** @private @const {!FileSystemMetadataProvider} */
+    this.fileSystemMetadataProvider_ = fileSystemMetadataProvider;
 
-  /**
-   * @private {!ContentMetadataProvider}
-   * @const
-   */
-  this.contentMetadataProvider_ = contentMetadataProvider;
+    /** @private @const {!ExternalMetadataProvider} */
+    this.externalMetadataProvider_ = externalMetadataProvider;
+
+    /** @private @const {!ContentMetadataProvider} */
+    this.contentMetadataProvider_ = contentMetadataProvider;
+
+    /** @private @const {!VolumeManager} */
+    this.volumeManager_ = volumeManager;
+  }
 
   /**
-   * @private {!VolumeManager}
-   * @const
+   * Obtains metadata for entries.
+   * @param {!Array<!MetadataRequest>} requests
+   * @return {!Promise<!Array<!MetadataItem>>}
    */
-  this.volumeManager_ = volumeManager;
-}
+  get(requests) {
+    const fileSystemRequests = [];
+    const externalRequests = [];
+    const contentRequests = [];
+    const fallbackContentRequests = [];
+    requests.forEach(request => {
+      // Group property names.
+      const fileSystemPropertyNames = [];
+      const externalPropertyNames = [];
+      const contentPropertyNames = [];
+      const fallbackContentPropertyNames = [];
+      for (let i = 0; i < request.names.length; i++) {
+        const name = request.names[i];
+        const isFileSystemProperty =
+            FileSystemMetadataProvider.PROPERTY_NAMES.indexOf(name) !== -1;
+        const isExternalProperty =
+            ExternalMetadataProvider.PROPERTY_NAMES.indexOf(name) !== -1;
+        const isContentProperty =
+            ContentMetadataProvider.PROPERTY_NAMES.indexOf(name) !== -1;
+        assert(isFileSystemProperty || isExternalProperty || isContentProperty);
+        assert(!(isFileSystemProperty && isContentProperty));
+        // If the property can be obtained both from ExternalProvider and from
+        // ContentProvider, we can obtain the property from ExternalProvider
+        // without fetching file content. On the other hand, the values from
+        // ExternalProvider may be out of sync if the file is 'dirty'. Thus we
+        // fallback to ContentProvider if the file is dirty. See below.
+        if (isExternalProperty && isContentProperty) {
+          externalPropertyNames.push(name);
+          fallbackContentPropertyNames.push(name);
+          continue;
+        }
+        if (isFileSystemProperty) {
+          fileSystemPropertyNames.push(name);
+        }
+        if (isExternalProperty) {
+          externalPropertyNames.push(name);
+        }
+        if (isContentProperty) {
+          contentPropertyNames.push(name);
+        }
+      }
+      const volumeInfo = this.volumeManager_.getVolumeInfo(request.entry);
+      const addRequests = (list, names) => {
+        if (names.length) {
+          list.push(new MetadataRequest(request.entry, names));
+        }
+      };
+      if (volumeInfo &&
+          (volumeInfo.volumeType === VolumeManagerCommon.VolumeType.DRIVE ||
+           volumeInfo.volumeType === VolumeManagerCommon.VolumeType.PROVIDED)) {
+        // Because properties can be out of sync just after sync completion
+        // even if 'dirty' is false, it refers 'present' here to switch the
+        // content and the external providers.
+        if (fallbackContentPropertyNames.length &&
+            externalPropertyNames.indexOf('present') === -1) {
+          externalPropertyNames.push('present');
+        }
+        addRequests(externalRequests, externalPropertyNames);
+        addRequests(contentRequests, contentPropertyNames);
+        addRequests(fallbackContentRequests, fallbackContentPropertyNames);
+      } else if (
+          volumeInfo &&
+          volumeInfo.volumeType ===
+              VolumeManagerCommon.VolumeType.DOCUMENTS_PROVIDER) {
+        // We need to discard content requests when using a documents provider
+        // since the content sniffing code can't resolve the file path in the
+        // MediaGallery API. See crbug.com/942417
+        addRequests(fileSystemRequests, fileSystemPropertyNames);
+        addRequests(
+            externalRequests,
+            MultiMetadataProvider.DOCUMENTS_PROVIDER_EXTERNAL_PROPERTY_NAMES);
+      } else {
+        addRequests(fileSystemRequests, fileSystemPropertyNames);
+        addRequests(
+            contentRequests,
+            contentPropertyNames.concat(fallbackContentPropertyNames));
+      }
+    });
+
+    const get = (provider, inRequests) => {
+      return provider.get(inRequests).then(results => {
+        return {
+          requests: inRequests,
+          results: results,
+        };
+      });
+    };
+    const fileSystemPromise =
+        get(this.fileSystemMetadataProvider_, fileSystemRequests);
+    const externalPromise =
+        get(this.externalMetadataProvider_, externalRequests);
+    const contentPromise = get(this.contentMetadataProvider_, contentRequests);
+    const fallbackContentPromise = externalPromise.then(requestsAndResults => {
+      const requests = requestsAndResults.requests;
+      const results = requestsAndResults.results;
+      const dirtyMap = [];
+      for (let i = 0; i < results.length; i++) {
+        dirtyMap[requests[i].entry.toURL()] = results[i].present;
+      }
+      return get(
+          this.contentMetadataProvider_,
+          fallbackContentRequests.filter(request => {
+            return dirtyMap[request.entry.toURL()];
+          }));
+    });
 
-MultiMetadataProvider.prototype.__proto__ = MetadataProvider.prototype;
+    // Merge results.
+    return Promise
+        .all([
+          fileSystemPromise,
+          externalPromise,
+          contentPromise,
+          fallbackContentPromise,
+        ])
+        .then(resultsList => {
+          const integratedResults = {};
+          for (let i = 0; i < resultsList.length; i++) {
+            const inRequests = resultsList[i].requests;
+            const results = resultsList[i].results;
+            assert(inRequests.length === results.length);
+            for (let j = 0; j < results.length; j++) {
+              const url = inRequests[j].entry.toURL();
+              integratedResults[url] =
+                  integratedResults[url] || new MetadataItem();
+              for (const name in results[j]) {
+                integratedResults[url][name] = results[j][name];
+              }
+            }
+          }
+          return requests.map(request => {
+            return integratedResults[request.entry.toURL()] ||
+                new MetadataItem();
+          });
+        });
+  }
+}
 
 /**
  * Property names of documents-provider files which we should get from
@@ -66,142 +191,3 @@ MultiMetadataProvider.DOCUMENTS_PROVIDER_EXTERNAL_PROPERTY_NAMES = [
   'canRename',
   'canAddChildren',
 ];
-
-/**
- * Obtains metadata for entries.
- * @param {!Array<!MetadataRequest>} requests
- * @return {!Promise<!Array<!MetadataItem>>}
- */
-MultiMetadataProvider.prototype.get = function(requests) {
-  const fileSystemRequests = [];
-  const externalRequests = [];
-  const contentRequests = [];
-  const fallbackContentRequests = [];
-  requests.forEach(request => {
-    // Group property names.
-    const fileSystemPropertyNames = [];
-    const externalPropertyNames = [];
-    const contentPropertyNames = [];
-    const fallbackContentPropertyNames = [];
-    for (let i = 0; i < request.names.length; i++) {
-      const name = request.names[i];
-      const isFileSystemProperty =
-          FileSystemMetadataProvider.PROPERTY_NAMES.indexOf(name) !== -1;
-      const isExternalProperty =
-          ExternalMetadataProvider.PROPERTY_NAMES.indexOf(name) !== -1;
-      const isContentProperty =
-          ContentMetadataProvider.PROPERTY_NAMES.indexOf(name) !== -1;
-      assert(isFileSystemProperty || isExternalProperty || isContentProperty);
-      assert(!(isFileSystemProperty && isContentProperty));
-      // If the property can be obtained both from ExternalProvider and from
-      // ContentProvider, we can obtain the property from ExternalProvider
-      // without fetching file content. On the other hand, the values from
-      // ExternalProvider may be out of sync if the file is 'dirty'. Thus we
-      // fallback to ContentProvider if the file is dirty. See below.
-      if (isExternalProperty && isContentProperty) {
-        externalPropertyNames.push(name);
-        fallbackContentPropertyNames.push(name);
-        continue;
-      }
-      if (isFileSystemProperty) {
-        fileSystemPropertyNames.push(name);
-      }
-      if (isExternalProperty) {
-        externalPropertyNames.push(name);
-      }
-      if (isContentProperty) {
-        contentPropertyNames.push(name);
-      }
-    }
-    const volumeInfo = this.volumeManager_.getVolumeInfo(request.entry);
-    const addRequests = (list, names) => {
-      if (names.length) {
-        list.push(new MetadataRequest(request.entry, names));
-      }
-    };
-    if (volumeInfo &&
-        (volumeInfo.volumeType === VolumeManagerCommon.VolumeType.DRIVE ||
-         volumeInfo.volumeType === VolumeManagerCommon.VolumeType.PROVIDED)) {
-      // Because properties can be out of sync just after sync completion
-      // even if 'dirty' is false, it refers 'present' here to switch the
-      // content and the external providers.
-      if (fallbackContentPropertyNames.length &&
-          externalPropertyNames.indexOf('present') === -1) {
-        externalPropertyNames.push('present');
-      }
-      addRequests(externalRequests, externalPropertyNames);
-      addRequests(contentRequests, contentPropertyNames);
-      addRequests(fallbackContentRequests, fallbackContentPropertyNames);
-    } else if (
-        volumeInfo &&
-        volumeInfo.volumeType ===
-            VolumeManagerCommon.VolumeType.DOCUMENTS_PROVIDER) {
-      // We need to discard content requests when using a documents provider
-      // since the content sniffing code can't resolve the file path in the
-      // MediaGallery API. See crbug.com/942417
-      addRequests(fileSystemRequests, fileSystemPropertyNames);
-      addRequests(
-          externalRequests,
-          MultiMetadataProvider.DOCUMENTS_PROVIDER_EXTERNAL_PROPERTY_NAMES);
-    } else {
-      addRequests(fileSystemRequests, fileSystemPropertyNames);
-      addRequests(
-          contentRequests,
-          contentPropertyNames.concat(fallbackContentPropertyNames));
-    }
-  });
-
-  const get = (provider, inRequests) => {
-    return provider.get(inRequests).then(results => {
-      return {
-        requests: inRequests,
-        results: results,
-      };
-    });
-  };
-  const fileSystemPromise =
-      get(this.fileSystemMetadataProvider_, fileSystemRequests);
-  const externalPromise = get(this.externalMetadataProvider_, externalRequests);
-  const contentPromise = get(this.contentMetadataProvider_, contentRequests);
-  const fallbackContentPromise = externalPromise.then(requestsAndResults => {
-    const requests = requestsAndResults.requests;
-    const results = requestsAndResults.results;
-    const dirtyMap = [];
-    for (let i = 0; i < results.length; i++) {
-      dirtyMap[requests[i].entry.toURL()] = results[i].present;
-    }
-    return get(
-        this.contentMetadataProvider_,
-        fallbackContentRequests.filter(request => {
-          return dirtyMap[request.entry.toURL()];
-        }));
-  });
-
-  // Merge results.
-  return Promise
-      .all([
-        fileSystemPromise,
-        externalPromise,
-        contentPromise,
-        fallbackContentPromise,
-      ])
-      .then(resultsList => {
-        const integratedResults = {};
-        for (let i = 0; i < resultsList.length; i++) {
-          const inRequests = resultsList[i].requests;
-          const results = resultsList[i].results;
-          assert(inRequests.length === results.length);
-          for (let j = 0; j < results.length; j++) {
-            const url = inRequests[j].entry.toURL();
-            integratedResults[url] =
-                integratedResults[url] || new MetadataItem();
-            for (const name in results[j]) {
-              integratedResults[url][name] = results[j][name];
-            }
-          }
-        }
-        return requests.map(request => {
-          return integratedResults[request.entry.toURL()] || new MetadataItem();
-        });
-      });
-};