Implement VMClassLoader's native methods.

Change-Id: I6e617f415e54ce29c3a0a470b58e79d3aaa0a4bf
diff --git a/src/java_lang_VMClassLoader.cc b/src/java_lang_VMClassLoader.cc
new file mode 100644
index 0000000..bed89d6
--- /dev/null
+++ b/src/java_lang_VMClassLoader.cc
@@ -0,0 +1,143 @@
+/*
+ * Copyright (C) 2008 The Android Open Source Project
+ *
+ * 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.
+ */
+
+#include "class_linker.h"
+#include "jni_internal.h"
+#include "ScopedUtfChars.h"
+#include "zip_archive.h"
+
+#include "JniConstants.h" // Last to avoid problems with LOG redefinition.
+
+namespace art {
+
+namespace {
+
+// Turn "java.lang.String" into "Ljava/lang/String;".
+std::string ToDescriptor(const char* class_name) {
+  std::string descriptor(class_name);
+  std::replace(descriptor.begin(), descriptor.end(), '.', '/');
+  if (descriptor.length() > 0 && descriptor[0] != '[') {
+    descriptor = "L" + descriptor + ";";
+  }
+  return descriptor;
+}
+
+jclass VMClassLoader_findLoadedClass(JNIEnv* env, jclass, jobject javaLoader, jstring javaName) {
+  ClassLoader* loader = Decode<ClassLoader*>(env, javaLoader);
+  ScopedUtfChars name(env, javaName);
+  if (name.c_str() == NULL) {
+    return NULL;
+  }
+
+  std::string descriptor(ToDescriptor(name.c_str()));
+  Class* c = Runtime::Current()->GetClassLinker()->LookupClass(descriptor.c_str(), loader);
+  return AddLocalReference<jclass>(env, c);
+}
+
+jint VMClassLoader_getBootClassPathSize(JNIEnv* env, jclass) {
+  return Runtime::Current()->GetClassLinker()->GetBootClassPath().size();
+}
+
+/*
+ * Returns a string URL for a resource with the specified 'javaName' in
+ * entry 'index' of the boot class path.
+ *
+ * We return a newly-allocated String in the following form:
+ *
+ *   jar:file://path!/name
+ *
+ * Where "path" is the bootstrap class path entry and "name" is the string
+ * passed into this method.  "path" needs to be an absolute path (starting
+ * with '/'); if it's not we'd need to make it absolute as part of forming
+ * the URL string.
+ */
+jstring VMClassLoader_getBootClassPathResource(JNIEnv* env, jclass, jstring javaName, jint index) {
+  ScopedUtfChars name(env, javaName);
+  if (name.c_str() == NULL) {
+    return NULL;
+  }
+
+  const std::vector<const DexFile*>& path = Runtime::Current()->GetClassLinker()->GetBootClassPath();
+  if (index < 0 || size_t(index) >= path.size()) {
+    return NULL;
+  }
+  const DexFile* dex_file = path[index];
+  const std::string& location(dex_file->GetLocation());
+  UniquePtr<ZipArchive> zip_archive(ZipArchive::Open(location));
+  if (zip_archive.get() == NULL) {
+    return NULL;
+  }
+  UniquePtr<ZipEntry> zip_entry(zip_archive->Find(name.c_str()));
+  if (zip_entry.get() == NULL) {
+    return NULL;
+  }
+
+  std::string url;
+  StringAppendF(&url, "jar:file://%s!/%s", location.c_str(), name.c_str());
+  return env->NewStringUTF(url.c_str());
+}
+
+/*
+ * static Class loadClass(String name, boolean resolve)
+ *     throws ClassNotFoundException
+ *
+ * Load class using bootstrap class loader.
+ *
+ * Return the Class object associated with the class or interface with
+ * the specified name.
+ *
+ * "name" is in "binary name" format, e.g. "dalvik.system.Debug$1".
+ */
+jclass VMClassLoader_loadClass(JNIEnv* env, jclass, jstring javaName, jboolean resolve) {
+  ScopedUtfChars name(env, javaName);
+  if (name.c_str() == NULL) {
+    return NULL;
+  }
+
+  /*
+   * We need to validate and convert the name (from x.y.z to x/y/z).  This
+   * is especially handy for array types, since we want to avoid
+   * auto-generating bogus array classes.
+   */
+  if (!IsValidClassName(name.c_str(), true, true)) {
+    Thread::Current()->ThrowNewException("Ljava/lang/ClassNotFoundException;",
+        "Invalid name: %s", name.c_str());
+    return NULL;
+  }
+
+  std::string descriptor(ToDescriptor(name.c_str()));
+  ClassLinker* class_linker = Runtime::Current()->GetClassLinker();
+  Class* c = class_linker->FindClass(descriptor.c_str(), NULL);
+  if (resolve) {
+    class_linker->EnsureInitialized(c, true);
+  }
+  return AddLocalReference<jclass>(env, c);
+}
+
+static JNINativeMethod gMethods[] = {
+  NATIVE_METHOD(VMClassLoader, findLoadedClass, "(Ljava/lang/ClassLoader;Ljava/lang/String;)Ljava/lang/Class;"),
+  NATIVE_METHOD(VMClassLoader, getBootClassPathResource, "(Ljava/lang/String;I)Ljava/lang/String;"),
+  NATIVE_METHOD(VMClassLoader, getBootClassPathSize, "()I"),
+  NATIVE_METHOD(VMClassLoader, loadClass, "(Ljava/lang/String;Z)Ljava/lang/Class;"),
+};
+
+}  // namespace
+
+void register_java_lang_VMClassLoader(JNIEnv* env) {
+  jniRegisterNativeMethods(env, "java/lang/VMClassLoader", gMethods, NELEM(gMethods));
+}
+
+}  // namespace art