From 1ba1e87ef07ffd4ff37cc12340c63367d698134e Mon Sep 17 00:00:00 2001
From: zsxwing <zsxwing@gmail.com>
Date: Tue, 4 Nov 2014 20:54:53 +0800
Subject: [PATCH] Check the API coverage in examples

---
 build.sbt                                     |   6 +-
 .../rx/lang/scala/examples/APICoverage.scala  | 108 ++++++++++++++++++
 2 files changed, 113 insertions(+), 1 deletion(-)
 create mode 100644 examples/src/test/scala/rx/lang/scala/examples/APICoverage.scala

diff --git a/build.sbt b/build.sbt
index d8bf1f45..36d7345a 100644
--- a/build.sbt
+++ b/build.sbt
@@ -4,7 +4,11 @@ name := "rxscala"
 
 lazy val root = project in file(".")
 
-lazy val examples = project in file("examples") dependsOn (root % "test->test;compile->compile")
+lazy val examples = project in file("examples") dependsOn (root % "test->test;compile->compile") settings(
+  libraryDependencies ++= Seq(
+    "org.apache.bcel" % "bcel" % "5.2" % "test"
+  )
+)
 
 scalacOptions in ThisBuild := Seq("-feature", "-unchecked", "-deprecation", "-encoding", "utf8")
 
diff --git a/examples/src/test/scala/rx/lang/scala/examples/APICoverage.scala b/examples/src/test/scala/rx/lang/scala/examples/APICoverage.scala
new file mode 100644
index 00000000..fca9dcd6
--- /dev/null
+++ b/examples/src/test/scala/rx/lang/scala/examples/APICoverage.scala
@@ -0,0 +1,108 @@
+/**
+ * Copyright 2014 Netflix, Inc.
+ *
+ * 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.
+ */
+package rx.lang.scala.examples
+
+import scala.collection.mutable
+
+import org.apache.bcel.Repository
+import org.apache.bcel.classfile.Utility
+import org.apache.bcel.util.ByteSequence
+import org.junit.Assert._
+import org.junit.Test
+import org.scalatest.junit.JUnitSuite
+
+class APICoverage extends JUnitSuite {
+
+  val INVOKEVIRTUAL_PREFIX = "invokevirtual\t"
+  val INVOKEINTERFACE_PREFIX = "invokeinterface\t"
+
+  def searchInvokedMethodsInClass(className : String): (Set[String], Set[String]) = {
+    val clazz = Repository.lookupClass(className)
+    val virtualMethods = mutable.Set[String]()
+    val interfaceMethods = mutable.Set[String]()
+    for (method <- clazz.getMethods) {
+      val code = method.getCode
+      if (code != null) {
+        val stream = new ByteSequence(code.getCode)
+        while (stream.available() > 0) {
+          val instruction = Utility.codeToString(stream, code.getConstantPool, false)
+          if (instruction.startsWith(INVOKEVIRTUAL_PREFIX)) {
+            // instruction is something like
+            // invokevirtual<tab>rx.lang.scala.Observable$.interval<space>(Lscala/concurrent/duration/Duration;)Lrx/lang/scala/Observable;
+            val invokedMethod = instruction.substring(INVOKEVIRTUAL_PREFIX.length).replaceAll(" ", "")
+            virtualMethods += invokedMethod
+          } else if (instruction.startsWith(INVOKEINTERFACE_PREFIX)) {
+            // instruction is something like
+            // invokeinterface<tab>rx.lang.scala.Observable.firstOrElse<space>(Lscala/Function0;)Lrx/lang/scala/Observable;2<tab>0
+            val invokedMethod = instruction.substring(INVOKEINTERFACE_PREFIX.length, instruction.lastIndexOf('\t') - 1).replaceAll(" ", "")
+            interfaceMethods += invokedMethod
+          }
+        }
+      }
+    }
+    (virtualMethods.toSet, interfaceMethods.toSet)
+  }
+
+  def searchInvokedMethodsInPackage(classInThisPackage: Class[_]): (Set[String], Set[String]) = {
+    val virtualMethods = mutable.Set[String]()
+    val interfaceMethods = mutable.Set[String]()
+    val packageName = classInThisPackage.getPackage.getName
+    val packageDir = new java.io.File(classInThisPackage.getResource(".").toURI)
+    for(file <- packageDir.listFiles if file.getName.endsWith(".class")) {
+      val simpleClassName = file.getName.substring(0, file.getName.length - ".class".length)
+      val className = packageName + "." + simpleClassName
+      val (vMethods, iMethods) = searchInvokedMethodsInClass(className)
+      virtualMethods ++= vMethods
+      interfaceMethods ++= iMethods
+    }
+    (virtualMethods.toSet, interfaceMethods.toSet)
+  }
+
+  val nonPublicAPIs = Set(
+    "<clinit>",
+    "jObsOfListToScObsOfSeq",
+    "jObsOfJObsToScObsOfScObs"
+  )
+
+  def getPublicMethods(className: String): Set[String] = {
+    val clazz = Repository.lookupClass(className)
+    clazz.getMethods.filter(method => method.isPublic && !nonPublicAPIs.contains(method.getName)).map {
+      method => className + "." + method.getName + method.getSignature
+    }.toSet
+  }
+
+  @Test
+  def assertExampleCoverage(): Unit = {
+    val objectMethods = getPublicMethods("rx.lang.scala.Observable$")
+    val classMethods = getPublicMethods("rx.lang.scala.Observable")
+
+    val (usedObjectMethods, usedClassMethods) = searchInvokedMethodsInPackage(getClass)
+
+    val uncoveredObjectMethods = objectMethods.diff(usedObjectMethods)
+    val uncoveredClassMethods = classMethods.diff(usedClassMethods)
+
+    if (uncoveredObjectMethods.nonEmpty || uncoveredClassMethods.nonEmpty) {
+      println("Please add examples for the following APIs")
+      uncoveredObjectMethods.foreach(println)
+      uncoveredClassMethods.foreach(println)
+    }
+
+    // TODO enable these assertions
+    // assertTrue("Please add missing examples", uncoveredObjectMethods.isEmpty)
+    // assertTrue("Please add missing examples", uncoveredClassMethods.isEmpty)
+  }
+
+}