travis: cache leveldb artifacts to reduce build time

.travis.yml

@@ -7,10 +7,7 @@ php:
 
 before_script:
  - phpenv config-rm xdebug.ini
- - LEVELDB_VERSION=10f59b56bec1db3ffe42ff265afe22182073e0e2
- - curl -fsSL "https://github.com/pmmp/leveldb-mcpe/archive/$LEVELDB_VERSION.tar.gz" | tar -zx
- - mv leveldb-mcpe-$LEVELDB_VERSION leveldb-mcpe
- - cd leveldb-mcpe && make -j4 sharedlibs && mv out-shared/libleveldb.* . && cd ..
+ - ./tests/build-leveldb.sh 10f59b56bec1db3ffe42ff265afe22182073e0e2
  - git clone https://github.com/reeze/php-leveldb.git leveldb
  - cd leveldb
  - git checkout 9bcae79f71b81a5c3ea6f67e45ae9ae9fb2775a5
@@ -47,5 +44,8 @@ script:
  - composer install --no-dev
  - ./tests/travis.sh -t4
 
+cache:
+ - leveldb-mcpe
+
 notifications:
  email: false

tests/build-leveldb.sh

@@ -0,0 +1,24 @@
+#!/bin/bash
+
+set -e
+
+LEVELDB_VERSION="$1"
+if [ ! -f "./leveldb-mcpe/built_version" ] || [ $(cat "./leveldb-mcpe/built_version") != "$LEVELDB_VERSION" ]; then
+    echo "Building new LevelDB"
+    rm -rf "./leveldb-mcpe" || true
+    mkdir "./leveldb-mcpe"
+
+    curl -fsSL "https://github.com/pmmp/leveldb-mcpe/archive/$LEVELDB_VERSION.tar.gz" | tar -zx
+    mv "./leveldb-mcpe-$LEVELDB_VERSION" leveldb-mcpe-build
+    cd leveldb-mcpe-build
+    make -j4 sharedlibs
+
+    #put the artifacts in a separate dir, to avoid bloating travis cache"
+    mv out-shared/libleveldb.* ../leveldb-mcpe
+    mv include ../leveldb-mcpe
+    cd ../leveldb-mcpe
+    echo "$LEVELDB_VERSION" > "./built_version"
+    cd ..
+else
+    echo "Using cached build for LevelDB version $LEVELDB_VERSION"
+fi