How node.js is integrated with chromium

node.js itself is not well prepared for being integrated into another project, so it would take some jobs to make it run in Chromium.

Replace Chromium's Message Pump

Chromium internally use class MessageLoop and MessagePump to support its events loop, since node uses libuv to support its events loop, we need to implement a new MessagePump which uses libuv as its underlying events library.

See base/message_pump_uv.cc, base/message_pump_uv.cc, base/message_loop.cc and base/message_loop.h to understand our work.

On Mac things are a lot different, see base/message_pump_mac.h and base/message_pump_mac.mm.

Modify node

Though node has a Start function that setups everything,it will redirect everything into its own message loop, so we split the Start function into several parts, see third_party/node/src/node.cc.

And since node itself expects to execute a script file, there are many logics that deal with script execution in third_party/node/src/node.js, we heavily modified that part and used some tricks to make its module system run under node-webkit.

Another modification resided under third_party/WebKit/Source/WebCore/bindings/v8/V8DOMWindowShell.cpp in line 363, we inserted some script after WebKit is initialized, so node can get a right pathname and filename which is vital to require function.

Insert node's symbols into webkit

This is the most important and trickiest part of node-webkit, first we initialize a context for node, and make node setup all its stuff under it, see content/renderer/renderer_main.cc, then when WebKit has installed DOM into its context, we move everything from node to WebKit, see third_party/WebKit/Source/WebCore/bindings/v8/V8DOMWindowShell.cpp in line 346.

A potential problem is that all node's callbacks will be executed under node's context, since the message loop runs under node's context. But all codes from <script> tag will run under WebKit's context, this could cause some problems since same codes under different contexts.