Add withClasspath(Iterable<File>) to Compiler and JavaSourcesSubject and deprecate withClasspathFrom(ClassLoader)

RELNOTES=Add `withClasspath(Iterable<File>)` to `Compiler` and `JavaSourcesSubject` and deprecate `withClasspathFrom(ClassLoader)`

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=185700333

Author: cushon

src/main/java/com/google/testing/compile/Compiler.java

@@ -16,29 +16,39 @@
 package com.google.testing.compile;
 
 import static com.google.common.base.Functions.toStringFunction;
+import static com.google.common.collect.ImmutableList.toImmutableList;
 import static java.nio.charset.StandardCharsets.UTF_8;
 import static javax.tools.ToolProvider.getSystemJavaCompiler;
 
 import com.google.auto.value.AutoValue;
-import com.google.common.base.Joiner;
+import com.google.common.annotations.VisibleForTesting;
+import com.google.common.base.Splitter;
 import com.google.common.base.StandardSystemProperty;
 import com.google.common.collect.FluentIterable;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableSet;
+import com.google.common.collect.Iterables;
 import com.google.testing.compile.Compilation.Status;
+import java.io.File;
+import java.io.IOException;
+import java.io.UncheckedIOException;
 import java.net.URL;
 import java.net.URLClassLoader;
 import java.util.LinkedHashSet;
 import java.util.Locale;
+import java.util.Optional;
 import java.util.Set;
 import javax.annotation.processing.Processor;
 import javax.tools.DiagnosticCollector;
 import javax.tools.JavaCompiler;
 import javax.tools.JavaCompiler.CompilationTask;
 import javax.tools.JavaFileObject;
+import javax.tools.StandardLocation;
 
 /** An object that can {@link #compile} Java source files. */
 @AutoValue
+// clashes with java.lang.Compiler (which is deprecated for removal in 9)
+@SuppressWarnings("JavaLangClash")
 public abstract class Compiler {
 
   /** Returns the {@code javac} compiler. */
@@ -48,7 +58,8 @@ public static Compiler javac() {
 
   /** Returns a {@link Compiler} that uses a given {@link JavaCompiler} instance. */
   public static Compiler compiler(JavaCompiler javaCompiler) {
-    return new AutoValue_Compiler(javaCompiler, ImmutableList.of(), ImmutableList.of());
+    return new AutoValue_Compiler(
+        javaCompiler, ImmutableList.of(), ImmutableList.of(), Optional.empty());
   }
 
   abstract JavaCompiler javaCompiler();
@@ -59,6 +70,9 @@ public static Compiler compiler(JavaCompiler javaCompiler) {
   /** The options passed to the compiler. */
   public abstract ImmutableList<String> options();
 
+  /** The compilation class path. If not present, the system class path is used. */
+  public abstract Optional<ImmutableList<File>> classPath();
+
   /**
    * Uses annotation processors during compilation. These replace any previously specified.
    *
@@ -78,7 +92,7 @@ public final Compiler withProcessors(Processor... processors) {
    * @return a new instance with the same options and the given processors
    */
   public final Compiler withProcessors(Iterable<? extends Processor> processors) {
-    return copy(ImmutableList.copyOf(processors), options());
+    return copy(ImmutableList.copyOf(processors), options(), classPath());
   }
 
   /**
@@ -96,21 +110,30 @@ public final Compiler withOptions(Object... options) {
    * @return a new instance with the same processors and the given options
    */
   public final Compiler withOptions(Iterable<?> options) {
-    return copy(processors(), FluentIterable.from(options).transform(toStringFunction()).toList());
+    return copy(
+        processors(),
+        FluentIterable.from(options).transform(toStringFunction()).toList(),
+        classPath());
   }
 
   /**
-   * Uses the classpath from the passed on classloader (and its parents) for the compilation
-   * instead of the system classpath.
+   * Uses the classpath from the passed on classloader (and its parents) for the compilation instead
+   * of the system classpath.
    *
    * @throws IllegalArgumentException if the given classloader had classpaths which we could not
    *     determine or use for compilation.
+   * @deprecated prefer {@link #withClasspath(Iterable)}. This method only supports {@link
+   *     URLClassLoader} and the default system classloader, and {@link File}s are usually a more
+   *     natural way to expression compilation classpaths than class loaders.
    */
+  @Deprecated
   public final Compiler withClasspathFrom(ClassLoader classloader) {
-    String classpath = getClasspathFromClassloader(classloader);
-    ImmutableList<String> options =
-        ImmutableList.<String>builder().add("-classpath").add(classpath).addAll(options()).build();
-    return copy(processors(), options);
+    return copy(processors(), options(), Optional.of(getClasspathFromClassloader(classloader)));
+  }
+
+  /** Uses the given classpath for the compilation instead of the system classpath. */
+  public final Compiler withClasspath(Iterable<File> classPath) {
+    return copy(processors(), options(), Optional.of(ImmutableList.copyOf(classPath)));
   }
 
   /**
@@ -132,6 +155,16 @@ public final Compilation compile(Iterable<? extends JavaFileObject> files) {
     InMemoryJavaFileManager fileManager =
         new InMemoryJavaFileManager(
             javaCompiler().getStandardFileManager(diagnosticCollector, Locale.getDefault(), UTF_8));
+    classPath()
+        .ifPresent(
+            classPath -> {
+              try {
+                fileManager.setLocation(StandardLocation.CLASS_PATH, classPath);
+              } catch (IOException e) {
+                // impossible by specification
+                throw new UncheckedIOException(e);
+              }
+            });
     CompilationTask task =
         javaCompiler()
             .getTask(
@@ -156,20 +189,38 @@ public final Compilation compile(Iterable<? extends JavaFileObject> files) {
     return compilation;
   }
 
+  @VisibleForTesting static final ClassLoader platformClassLoader = getPlatformClassLoader();
+
+  private static ClassLoader getPlatformClassLoader() {
+    try {
+      // JDK >= 9
+      return (ClassLoader) ClassLoader.class.getMethod("getPlatformClassLoader").invoke(null);
+    } catch (ReflectiveOperationException e) {
+      // Java <= 8
+      return null;
+    }
+  }
+
   /**
    * Returns the current classpaths of the given classloader including its parents.
    *
    * @throws IllegalArgumentException if the given classloader had classpaths which we could not
    *     determine or use for compilation.
    */
-  private static String getClasspathFromClassloader(ClassLoader currentClassloader) {
+  private static ImmutableList<File> getClasspathFromClassloader(ClassLoader currentClassloader) {
     ClassLoader systemClassLoader = ClassLoader.getSystemClassLoader();
 
     // Concatenate search paths from all classloaders in the hierarchy 'till the system classloader.
     Set<String> classpaths = new LinkedHashSet<>();
     while (true) {
       if (currentClassloader == systemClassLoader) {
-        classpaths.add(StandardSystemProperty.JAVA_CLASS_PATH.value());
+        Iterables.addAll(
+            classpaths,
+            Splitter.on(StandardSystemProperty.PATH_SEPARATOR.value())
+                .split(StandardSystemProperty.JAVA_CLASS_PATH.value()));
+        break;
+      }
+      if (currentClassloader == platformClassLoader) {
         break;
       }
       if (currentClassloader instanceof URLClassLoader) {
@@ -185,16 +236,21 @@ private static String getClasspathFromClassloader(ClassLoader currentClassloader
         }
       } else {
         throw new IllegalArgumentException(
-            "Classpath for compilation could not be extracted "
-                + "since given classloader is not an instance of URLClassloader");
+            String.format(
+                "Classpath for compilation could not be extracted "
+                    + "since %s is not an instance of URLClassloader",
+                currentClassloader));
       }
       currentClassloader = currentClassloader.getParent();
     }
 
-    return Joiner.on(StandardSystemProperty.PATH_SEPARATOR.value()).join(classpaths);
+    return classpaths.stream().map(File::new).collect(toImmutableList());
   }
 
-  private Compiler copy(ImmutableList<Processor> processors, ImmutableList<String> options) {
-    return new AutoValue_Compiler(javaCompiler(), processors, options);
+  private Compiler copy(
+      ImmutableList<Processor> processors,
+      ImmutableList<String> options,
+      Optional<ImmutableList<File>> classPath) {
+    return new AutoValue_Compiler(javaCompiler(), processors, options, classPath);
   }
 }

src/main/java/com/google/testing/compile/ForwardingStandardJavaFileManager.java

@@ -0,0 +1,71 @@
+/*
+ * Copyright (C) 2018 Google, 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 com.google.testing.compile;
+
+import java.io.File;
+import java.io.IOException;
+import javax.tools.ForwardingJavaFileManager;
+import javax.tools.JavaFileObject;
+import javax.tools.StandardJavaFileManager;
+
+/**
+ * Forwards calls to a given {@link StandardJavaFileManager}. Subclasses of this class might
+ * override some of these methods and might also provide additional fields and methods.
+ */
+class ForwardingStandardJavaFileManager extends ForwardingJavaFileManager<StandardJavaFileManager>
+    implements StandardJavaFileManager {
+
+  /**
+   * Creates a new instance of ForwardingStandardJavaFileManager.
+   *
+   * @param fileManager delegate to this file manager
+   */
+  ForwardingStandardJavaFileManager(StandardJavaFileManager fileManager) {
+    super(fileManager);
+  }
+
+  @Override
+  public Iterable<? extends JavaFileObject> getJavaFileObjectsFromFiles(
+      Iterable<? extends File> files) {
+    return fileManager.getJavaFileObjectsFromFiles(files);
+  }
+
+  @Override
+  public Iterable<? extends JavaFileObject> getJavaFileObjects(File... files) {
+    return fileManager.getJavaFileObjects(files);
+  }
+
+  @Override
+  public Iterable<? extends JavaFileObject> getJavaFileObjects(String... names) {
+    return fileManager.getJavaFileObjects(names);
+  }
+
+  @Override
+  public Iterable<? extends JavaFileObject> getJavaFileObjectsFromStrings(Iterable<String> names) {
+    return fileManager.getJavaFileObjectsFromStrings(names);
+  }
+
+  @Override
+  public void setLocation(Location location, Iterable<? extends File> path) throws IOException {
+    fileManager.setLocation(location, path);
+  }
+
+  @Override
+  public Iterable<? extends File> getLocation(Location location) {
+    return fileManager.getLocation(location);
+  }
+}

src/main/java/com/google/testing/compile/InMemoryJavaFileManager.java

@@ -34,11 +34,10 @@
 import java.nio.charset.Charset;
 import java.util.Map.Entry;
 import javax.tools.FileObject;
-import javax.tools.ForwardingJavaFileManager;
-import javax.tools.JavaFileManager;
 import javax.tools.JavaFileObject;
 import javax.tools.JavaFileObject.Kind;
 import javax.tools.SimpleJavaFileObject;
+import javax.tools.StandardJavaFileManager;
 import javax.tools.StandardLocation;
 
 /**
@@ -47,7 +46,7 @@
  * @author Gregory Kick
  */
 // TODO(gak): under java 1.7 this could all be done with a PathFileManager
-final class InMemoryJavaFileManager extends ForwardingJavaFileManager<JavaFileManager> {
+final class InMemoryJavaFileManager extends ForwardingStandardJavaFileManager {
   private final LoadingCache<URI, JavaFileObject> inMemoryFileObjects =
       CacheBuilder.newBuilder().build(new CacheLoader<URI, JavaFileObject>() {
         @Override
@@ -56,7 +55,7 @@ public JavaFileObject load(URI key) {
         }
       });
 
-  InMemoryJavaFileManager(JavaFileManager fileManager) {
+  InMemoryJavaFileManager(StandardJavaFileManager fileManager) {
     super(fileManager);
   }
 

src/main/java/com/google/testing/compile/JavaSourcesSubject.java

@@ -40,6 +40,7 @@
 import com.google.testing.compile.CompilationSubject.DiagnosticOnLine;
 import com.google.testing.compile.Parser.ParseResult;
 import com.sun.source.tree.CompilationUnitTree;
+import java.io.File;
 import java.io.IOException;
 import java.nio.charset.Charset;
 import java.util.ArrayList;
@@ -65,6 +66,7 @@ public final class JavaSourcesSubject
     implements CompileTester, ProcessedCompileTesterFactory {
   private final List<String> options = new ArrayList<String>(Arrays.asList("-Xlint"));
   @Nullable private ClassLoader classLoader;
+  @Nullable private ImmutableList<File> classPath;
 
   JavaSourcesSubject(FailureMetadata failureMetadata, Iterable<? extends JavaFileObject> subject) {
     super(failureMetadata, subject);
@@ -82,12 +84,24 @@ public JavaSourcesSubject withCompilerOptions(String... options) {
     return this;
   }
 
+  /**
+   * @deprecated prefer {@link #withClasspath(Iterable)}. This method only supports {@link
+   *     URLClassLoader} and the default system classloader, and {@link File}s are usually a more
+   *     natural way to expression compilation classpaths than class loaders.
+   */
+  @Deprecated
   @Override
   public JavaSourcesSubject withClasspathFrom(ClassLoader classLoader) {
     this.classLoader = classLoader;
     return this;
   }
 
+  @Override
+  public JavaSourcesSubject withClasspath(Iterable<File> classPath) {
+    this.classPath = ImmutableList.copyOf(classPath);
+    return this;
+  }
+
   @Override
   public CompileTester processedWith(Processor first, Processor... rest) {
     return processedWith(Lists.asList(first, rest));
@@ -312,6 +326,9 @@ private Compilation compilation() {
       if (classLoader != null) {
         compiler = compiler.withClasspathFrom(classLoader);
       }
+      if (classPath != null) {
+        compiler = compiler.withClasspath(classPath);
+      }
       return compiler.compile(actual());
     }
   }
@@ -577,11 +594,22 @@ public JavaSourcesSubject withCompilerOptions(String... options) {
       return delegate.withCompilerOptions(options);
     }
 
+    /**
+     * @deprecated prefer {@link #withClasspath(Iterable)}. This method only supports {@link
+     *     URLClassLoader} and the default system classloader, and {@link File}s are usually a more
+     *     natural way to expression compilation classpaths than class loaders.
+     */
+    @Deprecated
     @Override
     public JavaSourcesSubject withClasspathFrom(ClassLoader classLoader) {
       return delegate.withClasspathFrom(classLoader);
     }
 
+    @Override
+    public JavaSourcesSubject withClasspath(Iterable<File> classPath) {
+      return delegate.withClasspath(classPath);
+    }
+
     @Override
     public CompileTester processedWith(Processor first, Processor... rest) {
       return delegate.newCompilationClause(Lists.asList(first, rest));