refactor: extract electron downloading logic to its own script (#902)

This will allow us to easily re-use this functionality in the OS X
package script.

Signed-off-by: Juan Cruz Viotti <jviotti@openmailbox.org>

scripts/linux/package.sh

@@ -82,25 +82,12 @@ then
   usage
 fi
 
-OUTPUT_DIRNAME=$(dirname "$ARGV_OUTPUT")
+./scripts/unix/download-electron.sh \
-rm -rf "$ARGV_OUTPUT"
+  -r "$ARGV_ARCHITECTURE" \
-mkdir -p "$OUTPUT_DIRNAME"
+  -v "$ARGV_ELECTRON_VERSION" \
+  -s linux \
+  -o "$ARGV_OUTPUT"
 
-ELECTRON_ARCHITECTURE=$ARGV_ARCHITECTURE
-if [ "$ELECTRON_ARCHITECTURE" == "x86" ]; then
-  ELECTRON_ARCHITECTURE="ia32"
-fi
-
-ELECTRON_PACKAGE_OUTPUT=$OUTPUT_DIRNAME/$ARGV_APPLICATION_NAME-linux-$ARGV_ARCHITECTURE
-ELECTRON_GITHUB_REPOSITORY=https://github.com/electron/electron
-ELECTRON_FILENAME=electron-v$ARGV_ELECTRON_VERSION-linux-$ELECTRON_ARCHITECTURE.zip
-
-pushd $OUTPUT_DIRNAME
-wget $ELECTRON_GITHUB_REPOSITORY/releases/download/v$ARGV_ELECTRON_VERSION/$ELECTRON_FILENAME
-popd
-
-unzip $OUTPUT_DIRNAME/$ELECTRON_FILENAME -d $ARGV_OUTPUT
-rm $OUTPUT_DIRNAME/$ELECTRON_FILENAME
 mv $ARGV_OUTPUT/electron $ARGV_OUTPUT/$(echo "$ARGV_APPLICATION_NAME" | tr '[:upper:]' '[:lower:]')
 cp $ARGV_LICENSE $ARGV_OUTPUT/LICENSE
 echo "$ARGV_VERSION" > $ARGV_OUTPUT/version

scripts/unix/download-electron.sh

@@ -0,0 +1,79 @@
+#!/bin/bash
+
+###
+# Copyright 2016 resin.io
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+###
+
+set -u
+set -e
+
+if ! command -v wget 2>/dev/null 1>&2; then
+  echo "Dependency missing: wget" 1>&2
+  exit 1
+fi
+
+function usage() {
+  echo "Usage: $0"
+  echo ""
+  echo "Options"
+  echo ""
+  echo "    -r <electron architecture>"
+  echo "    -v <electron version>"
+  echo "    -s <electron operating system>"
+  echo "    -o <output directory>"
+  exit 0
+}
+
+ARGV_ARCHITECTURE=""
+ARGV_ELECTRON_VERSION=""
+ARGV_OPERATING_SYSTEM=""
+ARGV_OUTPUT=""
+
+while getopts ":r:v:s:o:" option; do
+  case $option in
+    r) ARGV_ARCHITECTURE=$OPTARG ;;
+    v) ARGV_ELECTRON_VERSION=$OPTARG ;;
+    s) ARGV_OPERATING_SYSTEM=$OPTARG ;;
+    o) ARGV_OUTPUT=$OPTARG ;;
+    *) usage ;;
+  esac
+done
+
+if [ -z "$ARGV_ARCHITECTURE" ] \
+  || [ -z "$ARGV_ELECTRON_VERSION" ] \
+  || [ -z "$ARGV_OPERATING_SYSTEM" ] \
+  || [ -z "$ARGV_OUTPUT" ]
+then
+  usage
+fi
+
+OUTPUT_DIRNAME=$(dirname "$ARGV_OUTPUT")
+rm -rf "$ARGV_OUTPUT"
+mkdir -p "$OUTPUT_DIRNAME"
+
+ELECTRON_ARCHITECTURE=$ARGV_ARCHITECTURE
+if [ "$ELECTRON_ARCHITECTURE" == "x86" ]; then
+  ELECTRON_ARCHITECTURE="ia32"
+fi
+
+ELECTRON_GITHUB_REPOSITORY=https://github.com/electron/electron
+ELECTRON_FILENAME="electron-v$ARGV_ELECTRON_VERSION-$ARGV_OPERATING_SYSTEM-$ELECTRON_ARCHITECTURE.zip"
+
+pushd "$OUTPUT_DIRNAME"
+wget "$ELECTRON_GITHUB_REPOSITORY/releases/download/v$ARGV_ELECTRON_VERSION/$ELECTRON_FILENAME"
+popd
+
+unzip "$OUTPUT_DIRNAME/$ELECTRON_FILENAME" -d "$ARGV_OUTPUT"
+rm "$OUTPUT_DIRNAME/$ELECTRON_FILENAME"