chore(android): generate snapshots at build time

.gitignore

@@ -35,9 +35,11 @@ android/.idea/modules.xml
 android/.idea/scopes/scope_settings.xml
 android/.idea/vcs.xml
 *.iml
+
 /iphone/TitaniumKit/Carthage
 /iphone/TitaniumKit/docs
 /iphone/TitaniumKit/build
 /iphone/lib/libTiCore.a
 
 .vscode/
+android/runtime/v8/src/native/V8Snapshots.h

android/build.xml

@@ -1,12 +1,8 @@
 <project name="titanium-mobile" default="build">
 	<property name="ti.android.root" location="${basedir}"/>
-
 	<import file="build/common.xml"/>
 
-	<target name="full.build" depends="clean,build">
-	</target>
-
+	<target name="full.build" depends="clean,build" />
 	<target name="clean" depends="clean.all" />
-
 	<target name="build" depends="build.all" />
 </project>

android/runtime/v8/src/native/V8Runtime.cpp

@@ -23,7 +23,7 @@
 #include "V8Util.h"
 
 #include "V8Runtime.h"
-#include "V8Snapshot.h"
+#include "V8Snapshots.h"
 
 #define TAG "V8Runtime"
 
@@ -226,7 +226,9 @@ JNIEXPORT void JNICALL Java_org_appcelerator_kroll_runtime_v8_V8Runtime_nativeIn
 		// Create a new Isolate and make it the current one.
 		Isolate::CreateParams create_params;
 		create_params.array_buffer_allocator = &allocator;
+#ifdef V8_SNAPSHOT_H
 		create_params.snapshot_blob = &snapshot;
+#endif
 		isolate = Isolate::New(create_params);
 		isolate->Enter();
 

android/runtime/v8/src/native/V8Snapshots.h

@@ -0,0 +1 @@
+// GENERATED AT BUILD TIME

build/lib/android/V8Snapshots.h.ejs

@@ -0,0 +1,24 @@
+#ifndef V8_SNAPSHOT_H
+#define V8_SNAPSHOT_H
+
+#include <v8.h>
+
+<% function DEFINE_SNAPSHOT (target, blob) { -%>
+<% if (!blob) return -%>
+#ifdef __<%- target -%>__
+static const unsigned char snapshot_data[] = {
+<% for (let i = 0; i < blob.length - 1; i++) { -%>
+<%- blob.readUInt8(i) + ',' -%>
+<% } -%>
+<%- blob.readUInt8(blob.length - 1) %>
+};
+#endif
+<% } -%>
+<% DEFINE_SNAPSHOT('i386', x86) -%>
+<% DEFINE_SNAPSHOT('arm', arm) -%>
+<% DEFINE_SNAPSHOT('aarch64', arm64) -%>
+
+static const int snapshot_size = sizeof(snapshot_data);
+static v8::StartupData snapshot = { (const char*) snapshot_data, snapshot_size };
+
+#endif

build/lib/android/index.js

@@ -2,6 +2,7 @@
 
 const path = require('path');
 const fs = require('fs-extra');
+const AndroidSDK = require('./androidsdk');
 const ant = require('./ant');
 const utils = require('../utils');
 const copyFile = utils.copyFile;
@@ -27,25 +28,32 @@ class Android {
 		this.apiLevel = options.apiLevel;
 		this.sdkVersion = options.sdkVersion;
 		this.gitHash = options.gitHash;
+		this.sdk = new AndroidSDK(this.androidSDK, this.apiLevel);
+		this.antProperties = {
+			'build.version': this.sdkVersion,
+			'build.githash': this.gitHash,
+			'android.sdk': this.sdk.getAndroidSDK(),
+			'android.platform': this.sdk.getPlatformDir(),
+			'google.apis': this.sdk.getGoogleApisDir(),
+			'kroll.v8.build.x86': 1,
+			'android.ndk': this.androidNDK
+		};
 	}
 
 	async clean() {
-		return ant.build(ANDROID_BUILD_XML, [ 'clean' ], {});
+		return ant.build(ANDROID_BUILD_XML, [ 'clean' ], this.antProperties);
 	}
 
 	async build() {
-		const AndroidSDK = require('./androidsdk');
-		const sdk = new AndroidSDK(this.androidSDK, this.apiLevel);
-		const properties = {
-			'build.version': this.sdkVersion,
-			'build.githash': this.gitHash,
-			'android.sdk': sdk.getAndroidSDK(),
-			'android.platform': sdk.getPlatformDir(),
-			'google.apis': sdk.getGoogleApisDir(),
-			'kroll.v8.build.x86': 1,
-			'android.ndk': this.androidNDK
-		};
-		return ant.build(ANDROID_BUILD_XML, [ 'full.build' ], properties);
+		// Clean build and download V8
+		await this.clean().catch(error => console.error(error));
+
+		// Generate snapshots
+		const snapshot = require('./snapshot');
+		await snapshot.build().catch(error => console.error(error));
+
+		// Build Titanium Android
+		return ant.build(ANDROID_BUILD_XML, [ 'build' ], this.antProperties);
 	}
 
 	async package(packager) {

build/lib/android/snapshot.js

@@ -0,0 +1,110 @@
+'use strict';
+
+const spawn = require('child_process').spawn; // eslint-disable-line security/detect-child-process
+const os = require('os');
+const fs = require('fs-extra');
+const path = require('path');
+const ejs = require('ejs');
+
+const ANDROID_DIR = path.resolve('..', 'android');
+const ANDROID_PROPS = require(path.join(ANDROID_DIR, 'package.json')); // eslint-disable-line security/detect-non-literal-require
+const V8_PROPS = ANDROID_PROPS.v8;
+const V8_LIB_DIR = path.join('..', 'dist', 'android', 'libv8', V8_PROPS.version, V8_PROPS.mode, 'libs');
+
+// Obtain target architectures
+const TARGETS = [];
+for (const target of ANDROID_PROPS.architectures) {
+	if (target === 'arm64-v8a') {
+		TARGETS.push('arm64');
+	} else if (target === 'armeabi-v7a') {
+		TARGETS.push('arm');
+	} else {
+		TARGETS.push(target);
+	}
+}
+
+/**
+ * Runs mksnapshot to generate snapshots for each architecture
+ * @param {string} target targets to generate blob
+ * @returns {Promise<void>}
+ */
+async function generateBlob(target) {
+	const V8_LIB_TARGET_DIR = path.resolve(V8_LIB_DIR, target);
+	const MKSNAPSHOT_PATH = path.join(V8_LIB_TARGET_DIR, 'mksnapshot');
+	const BLOB_PATH = path.join(V8_LIB_TARGET_DIR, 'blob.bin');
+	const args = [
+		'--startup_blob=' + BLOB_PATH
+	];
+
+	// Set correct permissions for 'mksnapshot'
+	fs.chmodSync(MKSNAPSHOT_PATH, 0o755);
+
+	return new Promise((resolve, reject) => {
+
+		// Snapshot already exists, skip...
+		if (fs.existsSync(BLOB_PATH)) {
+			resolve();
+		}
+
+		// Generate snapshot
+		const p = spawn(MKSNAPSHOT_PATH, args);
+		p.on('close', code => {
+			if (code !== 0) {
+				return reject(`"mksnapshot ${args.join(' ')}" failed with exit code: ${code}`);
+			}
+			resolve();
+		});
+	});
+}
+
+/**
+ * Generates V8Snapshots.h header from architecture blobs
+ * @returns {Promise<void>}
+ */
+async function generateHeader() {
+	const blobs = {};
+
+	// Load snapshots for each architecture
+	for (const target of TARGETS) {
+		const V8_LIB_TARGET_DIR = path.resolve(V8_LIB_DIR, target);
+		const BLOB_PATH = path.join(V8_LIB_TARGET_DIR, 'blob.bin');
+
+		if (fs.existsSync(BLOB_PATH)) {
+			blobs[target] = Buffer.from(fs.readFileSync(BLOB_PATH, 'binary'), 'binary');
+		}
+	}
+
+	return new Promise(async (resolve, reject) => {
+
+		// Generate 'V8Snapshots.h' from template
+		ejs.renderFile(path.join(__dirname, 'V8Snapshots.h.ejs'), blobs, {}, (error, output) => {
+			if (error) {
+				return reject(error);
+			}
+			fs.writeFileSync(path.join(ANDROID_DIR, 'runtime', 'v8', 'src', 'native', 'V8Snapshots.h'), output);
+			resolve();
+		});
+	});
+}
+
+/**
+ * Generates empty snapshot blobs for each supported architecture
+ * and creates a header to include the snapshots at build time.
+ * NOTE: SNAPSHOT GENERATION IS ONLY SUPPORTED ON macOS
+ * @returns {Promise<void>}
+ */
+async function build() {
+	return new Promise(async (resolve, reject) => {
+
+		// Only macOS is supports creating snapshots
+		if (os.platform() === 'darwin') {
+			for (const target of TARGETS) {
+				await generateBlob(target).catch(error => reject(error));
+			}
+			await generateHeader().catch(error => reject(error));
+		}
+		resolve();
+	});
+}
+
+module.exports = { build };