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js/goog/fs/blob.js

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+/**
+ * @license
+ * Copyright The Closure Library Authors.
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/**
+ * @fileoverview Wrappers for the HTML5 File API. These wrappers closely mirror
+ * the underlying APIs, but use Closure-style events and Deferred return values.
+ * Their existence also makes it possible to mock the FileSystem API for testing
+ * in browsers that don't support it natively.
+ *
+ * When adding public functions to anything under this namespace, be sure to add
+ * its mock counterpart to goog.testing.fs.
+ */
+
+goog.provide('goog.fs.blob');
+
+
+
+/**
+ * Concatenates one or more values together and converts them to a Blob.
+ *
+ * @param {...(string|!Blob|!ArrayBuffer)} var_args The values that will make up
+ *     the resulting blob.
+ * @return {!Blob} The blob.
+ */
+goog.fs.blob.getBlob = function(var_args) {
+  'use strict';
+  const BlobBuilder = goog.global.BlobBuilder || goog.global.WebKitBlobBuilder;
+
+  if (BlobBuilder !== undefined) {
+    const bb = new BlobBuilder();
+    for (let i = 0; i < arguments.length; i++) {
+      bb.append(arguments[i]);
+    }
+    return bb.getBlob();
+  } else {
+    return goog.fs.blob.getBlobWithProperties(
+        Array.prototype.slice.call(arguments));
+  }
+};
+
+
+/**
+ * Creates a blob with the given properties.
+ * See https://developer.mozilla.org/en-US/docs/Web/API/Blob for more details.
+ *
+ * @param {!Array<string|!Blob|!ArrayBuffer>} parts The values that will make up
+ *     the resulting blob (subset supported by both BlobBuilder.append() and
+ *     Blob constructor).
+ * @param {string=} opt_type The MIME type of the Blob.
+ * @param {string=} opt_endings Specifies how strings containing newlines are to
+ *     be written out.
+ * @return {!Blob} The blob.
+ */
+goog.fs.blob.getBlobWithProperties = function(parts, opt_type, opt_endings) {
+  'use strict';
+  const BlobBuilder = goog.global.BlobBuilder || goog.global.WebKitBlobBuilder;
+
+  if (BlobBuilder !== undefined) {
+    const bb = new BlobBuilder();
+    for (let i = 0; i < parts.length; i++) {
+      bb.append(parts[i], opt_endings);
+    }
+    return bb.getBlob(opt_type);
+  } else if (goog.global.Blob !== undefined) {
+    const properties = {};
+    if (opt_type) {
+      properties['type'] = opt_type;
+    }
+    if (opt_endings) {
+      properties['endings'] = opt_endings;
+    }
+    return new Blob(parts, properties);
+  } else {
+    throw new Error('This browser doesn\'t seem to support creating Blobs');
+  }
+};

js/goog/fs/url.js

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+/**
+ * @license
+ * Copyright The Closure Library Authors.
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/**
+ * @fileoverview Wrapper for URL and its createObjectUrl and revokeObjectUrl
+ * methods that are part of the HTML5 File API.
+ */
+
+goog.provide('goog.fs.url');
+
+
+/**
+ * Creates a blob URL for a blob object.
+ * Throws an error if the browser does not support Object Urls.
+ *
+ * @param {!File|!Blob|!MediaSource|!MediaStream} obj The object for which
+ *   to create the URL.
+ * @return {string} The URL for the object.
+ */
+goog.fs.url.createObjectUrl = function(obj) {
+  'use strict';
+  return goog.fs.url.getUrlObject_().createObjectURL(obj);
+};
+
+
+/**
+ * Revokes a URL created by {@link goog.fs.url.createObjectUrl}.
+ * Throws an error if the browser does not support Object Urls.
+ *
+ * @param {string} url The URL to revoke.
+ * @return {void}
+ */
+goog.fs.url.revokeObjectUrl = function(url) {
+  'use strict';
+  goog.fs.url.getUrlObject_().revokeObjectURL(url);
+};
+
+
+/**
+ * @record
+ * @private
+ */
+goog.fs.url.UrlObject_ = function() {};
+
+/**
+ * @param {!File|!Blob|!MediaSource|!MediaStream} arg
+ * @return {string}
+ */
+goog.fs.url.UrlObject_.prototype.createObjectURL = function(arg) {};
+
+/**
+ * @param {string} s
+ * @return {void}
+ */
+goog.fs.url.UrlObject_.prototype.revokeObjectURL = function(s) {};
+
+
+/**
+ * Get the object that has the createObjectURL and revokeObjectURL functions for
+ * this browser.
+ *
+ * @return {!goog.fs.url.UrlObject_} The object for this browser.
+ * @private
+ */
+goog.fs.url.getUrlObject_ = function() {
+  'use strict';
+  const urlObject = goog.fs.url.findUrlObject_();
+  if (urlObject != null) {
+    return urlObject;
+  } else {
+    throw new Error('This browser doesn\'t seem to support blob URLs');
+  }
+};
+
+
+/**
+ * Finds the object that has the createObjectURL and revokeObjectURL functions
+ * for this browser.
+ *
+ * @return {?goog.fs.url.UrlObject_} The object for this browser or null if the
+ *     browser does not support Object Urls.
+ * @private
+ */
+goog.fs.url.findUrlObject_ = function() {
+  'use strict';
+  // This is what the spec says to do
+  // http://dev.w3.org/2006/webapi/FileAPI/#dfn-createObjectURL
+  if (goog.global.URL !== undefined &&
+      goog.global.URL.createObjectURL !== undefined) {
+    return /** @type {!goog.fs.url.UrlObject_} */ (goog.global.URL);
+    // This is what the spec used to say to do
+  } else if (goog.global.createObjectURL !== undefined) {
+    return /** @type {!goog.fs.url.UrlObject_} */ (goog.global);
+  } else {
+    return null;
+  }
+};
+
+
+/**
+ * Checks whether this browser supports Object Urls. If not, calls to
+ * createObjectUrl and revokeObjectUrl will result in an error.
+ *
+ * @return {boolean} True if this browser supports Object Urls.
+ */
+goog.fs.url.browserSupportsObjectUrls = function() {
+  'use strict';
+  return goog.fs.url.findUrlObject_() != null;
+};