CSC/ECE 517 Fall 2014/oss M1453 sst

Expand the coverage of the developer tools for inspecting web content in Servo remotely from a Firefox browser - requires the ability to read JavaScript code in Firefox

Background Information

Firefox supports remote debugging - ie. communicating with an arbitrary server that implements a protocol for exposing information about web content. Servo implements a very basic developer tools server that currently supports executing JS remotely and investigating the DOM tree in the document inspector. We want to expand these capabilities by allowing remote modification of the DOM tree, better JS console integration (exposing historical and real-time exceptions), and enabling server->client messages that are not responses to client->server messages.

Developer tools

The Mozilla debugging protocol allows a debugger to connect to a browser, discover what sorts of things are present to debug or inspect, select JavaScript threads to watch, and observe and modify their execution. The protocol provides a unified view of JavaScript, DOM nodes, CSS rules, and the other technologies used in client-side web applications. The protocol ought to be sufficiently general to be extended for use with other sorts of clients (profilers, say) and servers (mail readers; random XULrunner applications).

All communication between debugger (client) and browser (server) is in the form of JSON objects. This makes the protocol directly readable by humans, capable of graceful evolution, and easy to implement using stock libraries. In particular, it should be easy to create mock implementations for testing and experimentation.

The protocol operates at the JavaScript level, not at the C++ or machine level, and assumes that the JavaScript implementation itself is healthy and responsive. The JavaScript program being executed may well have gone wrong, but the JavaScript implementation's internal state must not be corrupt. Bugs in the implementation may cause the debugger to fail; bugs in the interpreted program must not.

Reference: https://wiki.mozilla.org/Remote_Debugging_Protocol

Servo

Servo is an experimental web browser layout engine being developed by Mozilla Research, with Samsung porting it to Android and ARM processors. The prototype seeks to create a highly parallel environment, in which many components (such as rendering, layout, HTML parsing, image decoding, etc.) are handled by fine-grained, isolated tasks. Servo builds on top of Rust to provide a secure and reliable foundation. Memory safety at the core of the platform ensures a high degree of assurance in the browser’s trusted computing base. Rust’s lightweight task mechanism also promises to allow fine-grained isolation between browser components, such as tabs and extensions, without the need for expensive runtime protection schemes, like operating system process isolation.

Building and running servo On OS X (homebrew):

    brew install automake pkg-config python glfw3 cmake
    pip install virtualenv

On OS X (MacPorts):

    sudo port install python27 py27-virtualenv cmake

On Debian-based Linuxes:

   sudo apt-get install curl freeglut3-dev \
   libfreetype6-dev libgl1-mesa-dri libglib2.0-dev xorg-dev \
   msttcorefonts gperf g++ cmake python-virtualenv \
   libssl-dev libglfw-dev

On Fedora:

   sudo yum install curl freeglut-devel libtool gcc-c++ libXi-devel \
   freetype-devel mesa-libGL-devel glib2-devel libX11-devel libXrandr-devel gperf \
   fontconfig-devel cabextract ttmkfdir python python-virtualenv expat-devel \
   rpm-build openssl-devel glfw-devel cmake
pushd .
cd /tmp
wget http://corefonts.sourceforge.net/msttcorefonts-2.5-1.spec
rpmbuild -bb msttcorefonts-2.5-1.spec
sudo yum install $HOME/rpmbuild/RPMS/noarch/msttcorefonts-2.5-1.noarch.rpm
popd

On Arch Linux:

   sudo pacman -S base-devel git python2 python2-virtualenv mesa glfw ttf-font cmake

Rust

Rust is a new programming language for developing reliable and efficient systems. It's designed to support concurrency and parallelism in building platforms that take full advantage of modern hardware. Its static type system is safe and expressive and it provides strong guarantees about isolation, concurrency execution and memory safety.

Rust combines powerful and flexible modern programming constructs with a clear performance model to make program efficiency predictable and manageable. One important way it achieves this is by allowing fine-grained control over memory allocation through contiguous records and stack allocation. This control is balanced with the absolute requirement of safety: Rust’s type system and runtime guarantee the absence of data races, buffer overflow, stack overflow or access to uninitialized or deallocated memory. There are a number of ways to install Rust, but the easiest is to use the rustup script. If you're on Linux or a Mac, all you need to do is this:

    $ curl -s https://static.rust-lang.org/rustup.sh | sudo sh

(If you're concerned about curl | sudo sh, check references) If you're on Windows, please download either the 32-bit installer or the 64-bit installer and run it.

Uninstalling Rust

   $ curl -s https://static.rust-lang.org/rustup.sh | sudo sh -s -- --uninstall

If you used the Windows installer, just re-run the .exe and it will give you an uninstall option.

Reference : http://doc.rust-lang.org Download Rust: http://www.rust-lang.org/

Project Description

The project involves the enhancement of

Future Scope

• Separate devtools event handling from script handling tasks.
• Implement client server messages to update the attribute values of a HTML node.
• Send a console message to the developer tools server.
• Synchronously fetch the cached messages from tasks.
• Create an error reporter for error logging and notification.
• Dynamic buffering and sending of messages to Developer Tools.
• Support for disparate client reading and writing.
• Send a detailed error message to the client when an error is reported to the tasks.

References

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