Clone this repo:


  1. 17f8da6 double-clicking an already-mounted .zip file should open the archive by Kazuki Takise · 5 weeks ago master
  2. 3ee5d5a Fix libarchive build as naclports was moved to webports. by Mihail Costea · 7 months ago
  3. 7c41f94 Update URLs by Mike Frysinger · 11 months ago
  4. 61d2406 Merge "libarchive-fork: pass explicit disable flags for libs" by Mike Frysinger · 12 months ago
  5. adf6924 Merge "README: improve build insns" by Mike Frysinger · 12 months ago

ZIP Unpacker extension

This is the ZIP Unpacker extension used in Chrome OS to support reading and unpacking of zip archives.

Build steps


Since the code is built with NaCl, you‘ll need its toolchain. See the download page. The install location does not matter as it’ll be set via NACL_SDK_ROOT.

You should install the current stable version.

$ wget
$ unzip -u
$ ./nacl_sdk/naclsdk install

Then configure the path to the root of the specific SDK version.

# This assumes there's only one version of the SDK.
$ export NACL_SDK_ROOT=$(echo ${PWD}/nacl_sdk/pepper_*)

Webports (a.k.a. NaCl ports)

We'll use libraries from webports. See How to Checkout.

The install location does not matter as it'll be set via WEBPORTS_PATH.

Make sure to checkout the branch that matches the version of the SDK you‘re using. If you’re using pepper_47, then check out the pepper_47 branch.

$ cd src
$ branch=$(basename "${NACL_SDK_ROOT}")
$ git checkout -b ${branch} remotes/origin/${branch}
$ cd ..

npm Setup

First install npm using your normal packaging system. On Debian, you'll want something like:

$ sudo apt-get install npm

Then install the npm modules that we require. Do this in the root of the unpacker repo.

$ npm install bower 'vulcanize@<0.8'

Unpacker Build

Once done, install the libarchive-fork from third-party of the unpacker project. Note that you cannot use libarchive nor libarchive-dev packages from webports at this moment, as not all patches in the fork are upstreamed.

$ cd third-party
$ make libarchive-fork

Polymer is used for UI. In order to fetch it, in the same directory type:

$ make polymer

Build the PNaCl module.

$ cd unpacker
$ make [debug]


The package can be found in the release or debug directory. You can run it directly from there using Chrome's “Load unpacked extension” feature, or you can zip it up for posting to the Chrome Web Store.

$ zip -r release/

Once it's loaded, you should be able to open ZIP archives in the Files app.


To see debug messages open chrome from a terminal and check the output. For output redirection see


Install Karma for tests runner, Mocha for asynchronous testings, Chai for assertions, and Sinon for spies and stubs.

$ npm install karma --save-dev
$ npm install karma-chrome-launcher --save-dev
$ npm install -g karma-cli
$ npm install mocha --save-dev
$ npm install karma-mocha --save-dev
$ npm install karma-chai --save-dev
$ npm install karma-sinon --save-dev
$ npm install karma-chrome-launcher --save-dev

# Run tests:
$ cd unpacker-test
$ ./  # JavaScript tests.
$ ./  # C++ tests.

# Check JavaScript code using the Closure JS Compiler.
# See
$ cd unpacker
$ npm install google-closure-compiler
$ bash