mojo: Create a basic clipboard.

mojo/services/public/interfaces/clipboard/clipboard.mojom

+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+module mojo {
+
+interface Clipboard {
+  enum Type {
+    COPY_PASTE,
+    SELECTION,
+    DRAG
+  };
+
+  // Mime type constants
+  const string MIME_TYPE_TEXT = "text/plain";
+  const string MIME_TYPE_HTML = "text/html";
+
+  // Returns a sequence number which uniquely identifies clipboard state. This
+  // number is monotonically increasing, is increased when the clipboard state
+  // changes, and is provided by all major operating systems (Win, Linux, Mac).

[sky, 2014/09/11 22:11:43]

nit: no need to say provided by all major OSs here.

+  GetSequenceNumber(Type clipboard_type) => (uint64 sequence);
+
+  // Returns the available mime types. (Note: the chrome interface has a
+  // |contains_filenames| parameter here, but it appears to always be set
+  // to false.)
+  GetAvailableFormatMimeTypes(Type clipboard_types) => (string[] types);
+
+  ReadPlainText(Type clipboard_type) => (string text);

[sky, 2014/09/11 22:11:43]

Seems like the return type should be nullable. In so far as if plain text isn't
on the clipboard then shouldn't null be sent back? This applies to all other
ones.

+  ReadHTML(Type clipboard_type) =>

[sky, 2014/09/11 22:11:43]

Can html and plain text be expressed as a mime type so that there is only one
read function?

+      (string html, string url, uint32 fragment_start, uint32 fragment_end);
+  ReadMIMEType(Type clipboard_type, string mime_type) => (string data);
+  // TODO: We probably want an image type.
+
+  // Clipboard Writing
+  //
+  // Clipboard writing is a two phase operation, where a client queues all data
+  // types that they want written to the clipboard, and then writes all queued
+  // data in one pass. We do this to prevent racing with other applications on
+  // the system.
+
+  // Queue writing individual datatypes to specific clipboards.
+  QueueWritePlainText(Type clipboard_type, string text);

[sky, 2014/09/11 22:11:43]

Two staged commit seems best done in the client. Could the interface be SetData
that takes a list of mime-type and data pairs?

+  QueueWriteHTML(Type clipboard_type, string html_text, string url);
+  QueueWriteMIMEType(Type clipboard_type, string mime_type, string data);
+  // TODO: We probably want an image type.
+
+  // Writes all queued data types in one pass.
+  WriteQueuedData(Type clipboard_type);
+};
+
+}  // module mojo