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-rw-r--r--browser/components/newtab/PreviewProvider.jsm49
1 files changed, 49 insertions, 0 deletions
diff --git a/browser/components/newtab/PreviewProvider.jsm b/browser/components/newtab/PreviewProvider.jsm
new file mode 100644
index 000000000..8624b8544
--- /dev/null
+++ b/browser/components/newtab/PreviewProvider.jsm
@@ -0,0 +1,49 @@
+/* global XPCOMUtils, BackgroundPageThumbs, FileUtils, PageThumbsStorage, Task, MIMEService */
+/* exported PreviewProvider */
+
+"use strict";
+
+this.EXPORTED_SYMBOLS = ["PreviewProvider"];
+
+const {utils: Cu} = Components;
+Cu.import("resource://gre/modules/XPCOMUtils.jsm");
+Cu.import("resource://gre/modules/Task.jsm");
+Cu.import("resource://gre/modules/PageThumbs.jsm");
+Cu.import("resource://gre/modules/FileUtils.jsm");
+const {OS} = Cu.import("resource://gre/modules/osfile.jsm");
+
+XPCOMUtils.defineLazyModuleGetter(this, "BackgroundPageThumbs",
+ "resource://gre/modules/BackgroundPageThumbs.jsm");
+XPCOMUtils.defineLazyServiceGetter(this, "MIMEService",
+ "@mozilla.org/mime;1", "nsIMIMEService");
+
+let PreviewProvider = {
+ /**
+ * Returns a thumbnail as a data URI for a url, creating it if necessary
+ *
+ * @param {String} url
+ * a url to obtain a thumbnail for
+ * @return {Promise} A Promise that resolves with a base64 encoded thumbnail
+ */
+ getThumbnail: Task.async(function* PreviewProvider_getThumbnail(url) {
+ try {
+ yield BackgroundPageThumbs.captureIfMissing(url);
+ let imgPath = PageThumbsStorage.getFilePathForURL(url);
+
+ // OS.File object used to easily read off-thread
+ let file = yield OS.File.open(imgPath, {read: true, existing: true});
+
+ // nsIFile object needed for MIMEService
+ let nsFile = FileUtils.File(imgPath);
+
+ let contentType = MIMEService.getTypeFromFile(nsFile);
+ let bytes = yield file.read();
+ let encodedData = btoa(String.fromCharCode.apply(null, bytes));
+ file.close();
+ return `data:${contentType};base64,${encodedData}`;
+ } catch (err) {
+ Cu.reportError(`PreviewProvider_getThumbnail error: ${err}`);
+ throw err;
+ }
+ })
+};