misc/androidstudio: change GobindPlugin parameters

Plugin version 0.2.2:

While debugging golang/go#11895 I noticed the PATH param is less
intuitive that I hoped for. This change makes the plugin requires
instead:

   pkg: the package to compile
   GOMOBILE: absolute path to gomobile
   GO: absolute path to go
   GOPATH: gopath.

GOMOBILE/GO params are optional if Android Studio is configured
to include right paths in its environment.

Additional changes included in this cl:
  - GOMOBILEFLAGS param for users to optionally specify gomobile
    options e.g. -v -x which will be useful for debugging.
  - Set src/target java version to 1.7. Previous versions of plugins
    were compiled with JDK8 by accident, which prevented use of
    the android studio recommended JDK7.

Change-Id: Ie7818eb20c5220b16ed0ebccfb91520fe03e6ccd
Reviewed-on: https://go-review.googlesource.com/12923
Reviewed-by: David Crawshaw <crawshaw@golang.org>

misc/androidstudio/README.md

@@ -5,7 +5,7 @@ gobindPlugin invokes gomobile bind command on the specified package.
 build.gradle:
 <pre>
 plugins {
-  id "org.golang.mobile.bind" version "0.2.1"
+  id "org.golang.mobile.bind" version "0.2.2"
 }
 
 gobind {
@@ -15,8 +15,11 @@ gobind {
   // GOPATH
   GOPATH "/home/gopher"
 
-  // PATH to directories with "go" and "gomobile" tools.
-  PATH "path1:path2:"
+  // Absolute path to the gomobile binary
+  GOMOBILE "/mypath/bin/gomobile"
+
+  // Absolute path to the go binary
+  GO "/usr/local/go/bin/go"
 }
 </pre>
 

misc/androidstudio/build.gradle

@@ -1,5 +1,9 @@
 apply plugin: 'groovy'
 
+// Many android users still use JDK7.
+sourceCompatibility = '1.7'
+targetCompatibility = '1.7'
+
 buildscript {
   repositories {
     maven {
@@ -24,10 +28,10 @@ dependencies {
 }
 
 pluginBundle {
-  website = 'https://golang.org'
-  vcsUrl = 'https://github.com/golang/mobile'
+  website = 'https://golang.org/x/mobile'
+  vcsUrl = 'https://golang.org/x/mobile'
   description = 'Plugin for gomobile projects (beta)'
-  version = '0.2.1'
+  version = '0.2.2'
 
   plugins {
     gobindPlugin {

misc/androidstudio/src/main/groovy/org/golang/mobile/GobindPlugin.groovy

@@ -46,13 +46,30 @@ class GobindTask extends DefaultTask implements OutputFileTask {
 
 	@TaskAction
 	def gobind() {
-	    def pkg = project.gobind.pkg.trim()
-	    def gopath = project.gobind.GOPATH.trim()
-	    def paths = project.gobind.PATH.trim() + File.pathSeparator + System.getenv("PATH")
+	    def pkg = project.gobind.pkg
+	    def gopath = (project.gobind.GOPATH ?: System.getenv("GOPATH"))?.trim()
 	    if (!pkg || !gopath) {
 		throw new GradleException('gobind.pkg and gobind.GOPATH must be set')
 	    }
-	    def gomobile = findGomobile()
+
+	    def paths = (gopath.split(File.pathSeparator).collect{ "$it/bin" } +
+			System.getenv("PATH").split(File.pathSeparator)).flatten()
+	    // Default installation path of go distribution.
+	    if (isWindows()) {
+		paths = paths + "c:\\Go\\bin"
+	    } else {
+		paths = paths + "/usr/local/go/bin"
+	    }
+
+	    def gomobile = (project.gobind.GOMOBILE ?: findExecutable("gomobile", paths))?.trim()
+	    def gobin = (project.gobind.GO ?: findExecutable("go", paths))?.trim()
+	    def gomobileFlags = project.gobind.GOMOBILEFLAGS?.trim()
+
+	    if (!gomobile || !gobin) {
+		throw new GradleException('failed to find gomobile/go tools. Set gobind.GOMOBILE and gobind.GO')
+	    }
+
+	    paths = [findDir(gomobile), findDir(gobin), paths].flatten()
 
 	    Properties properties = new Properties()
 	    properties.load(project.rootProject.file('local.properties').newDataInputStream())
@@ -65,39 +82,62 @@ class GobindTask extends DefaultTask implements OutputFileTask {
             project.exec {
 		executable(gomobile)
 
-                args("bind", "-target=android", "-i", "-o", project.name+".aar", pkg)
+		def cmd = ["bind", "-target=android", "-i", "-o", project.name+".aar"]
+		if (gomobileFlags) {
+			cmd = (cmd+gomobileFlags.split(" ")).flatten()
+		}
+		cmd << pkg
+
+                args(cmd)
 		if (!androidHome?.trim()) {
 			throw new GradleException('Neither sdk.dir or ANDROID_HOME is set')
 		}
 		environment("GOPATH", gopath)
-		environment("PATH", paths)
+		environment("PATH", paths.join(File.pathSeparator))
 		environment("ANDROID_HOME", androidHome)
 	    }
         }
 
-	def findGomobile() {
-	    def gomobile = "gomobile"
-	    if (System.getProperty("os.name").startsWith("Windows")) {
-		gomobile = "gomobile.exe"
-	    }
-	    def paths = project.gobind.PATH + File.pathSeparator + System.getenv("PATH")
-	    for (p in paths.split(File.pathSeparator)) {
-		def f = new File(p + File.separator + gomobile)
-		if (f.exists()) {
-			return p + File.separator + gomobile
+	def isWindows() {
+		return System.getProperty("os.name").startsWith("Windows")
+	}
+
+	def findExecutable(String name, ArrayList<String> paths) {
+		if (isWindows() && !name.endsWith(".exe")) {
+			name = name + ".exe"
 		}
-	    }
-	    throw new GradleException('failed to find gomobile command from ' + paths)
+		for (p in paths) {
+		   def f = new File(p + File.separator + name)
+		   if (f.exists()) {
+			return p + File.separator + name
+		   }
+		}
+		throw new GradleException('binary ' + name + ' is not found in $PATH (' + paths + ')')
+	}
+
+	def findDir(String binpath) {
+		if (!binpath) {
+			return ""
+		}
+
+		def f = new File(binpath)
+		return f.getParentFile().getAbsolutePath();
 	}
 }
 
 class GobindExtension {
-    // Package to bind.
+    // Package to bind. (required)
     def String pkg = ""
 
-    // GOPATH: necessary for gomobile tool.
+    // GOPATH: necessary for gomobile tool. (required)
     def String GOPATH = System.getenv("GOPATH")
 
-    // PATH: must include path to 'gomobile' and 'go' binary.
-    def String PATH = ""
+    // GO: path to go tool. (can omit if 'go' is in the paths visible by Android Studio)
+    def String GO = ""
+
+    // GOMOBILE: path to gomobile binary. (can omit if 'gomobile' is under GOPATH)
+    def String GOMOBILE = ""
+
+    // GOMOBILEFLAGS: extra flags to be passed to gomobile command. (optional)
+    def String GOMOBILEFLAGS = ""
 }