PHPLIB-324: Cache extension installation for Travis CI jobs

.travis.yml

@@ -11,6 +11,7 @@ cache:
   directories:
     - ${HOME}/.cache/pip
     - ${HOME}/.composer/cache/files
+    - ${HOME}/php-ext
 
 env:
   global:
@@ -46,11 +47,28 @@ before_install:
   - mongod --version
   - mongo-orchestration --version
   - export MO_PATH=`python -c 'import mongo_orchestration; from os import path; print(path.dirname(mongo_orchestration.__file__));'`
+  - |
+    INI=~/.phpenv/versions/$(phpenv version-name)/etc/conf.d/travis.ini
+    # tpecl is a helper to compile and cache php extensions
+      tpecl () {
+          local ext_name=$1
+          local ext_so=$2
+          local ext_dir=$(php -r "echo ini_get('extension_dir');")
+          local ext_cache=~/php-ext/$(basename $ext_dir)/$ext_name
+          if [[ -e $ext_cache/$ext_so ]]; then
+              echo extension = $ext_cache/$ext_so >> $INI
+          else
+              mkdir -p $ext_cache
+              echo yes | pecl install -f $ext_name &&
+              cp $ext_dir/$ext_so $ext_cache
+          fi
+      }
+      export -f tpecl
 
 before_script:
   - mongo-orchestration start
   - pushd ${MO_PATH} && ${TRAVIS_BUILD_DIR}/.travis/mo.sh configurations/servers/clean.json start && popd
-  - pecl install -f mongodb-${DRIVER_VERSION}
+  - tpecl mongodb-${DRIVER_VERSION} mongodb.so
   - php --ri mongodb
   - composer install --no-interaction --no-progress --no-suggest
   - ulimit -c