base/android/java/templates/NativeLibraries.template

// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

package org.chromium.base.library_loader;

import org.chromium.base.annotations.SuppressFBWarnings;

@SuppressFBWarnings
public class NativeLibraries {
    /**
     * IMPORTANT NOTE: The variables defined here must _not_ be 'final'.
     *
     * The reason for this is very subtle:
     *
     * - This template is used to generate several distinct, but similar
     *   files used in different contexts:
     *
     *   o .../gen/templates/org/chromium/base/library_loader/NativeLibraries.java
     *
     *     This file is used to build base.jar, which is the library
     *     jar used by chromium projects. However, the
     *     corresponding NativeLibraries.class file will _not_ be part
     *     of the final base.jar.
     *
     *   o .../$PROJECT/native_libraries_java/NativeLibraries.java
     *
     *     This file is used to build an APK (e.g. $PROJECT
     *     could be 'content_shell_apk'). Its content will depend on
     *     this target's specific build configuration, and differ from
     *     the source file above.
     *
     * - During the final link, all .jar files are linked together into
     *   a single .dex file, and the second version of NativeLibraries.class
     *   will be put into the final output file, and used at runtime.
     *
     * - If the variables were defined as 'final', their value would be
     *   optimized out inside of 'base.jar', and could not be specialized
     *   for every chromium program. This, however, doesn't apply to arrays of
     *   strings, which can be defined as final.
     *
     * This exotic scheme is used to avoid injecting project-specific, or
     * even build-specific, values into the base layer. E.g. this is
     * how the component build is supported on Android without modifying
     * the sources of each and every Chromium-based target.
     */

#if defined(ENABLE_CHROMIUM_LINKER_LIBRARY_IN_ZIP_FILE) && \
    !defined(ENABLE_CHROMIUM_LINKER)
#error "Must have ENABLE_CHROMIUM_LINKER to enable library in zip file"
#endif

    // Set to true to enable the use of the Chromium Linker.
#if defined(ENABLE_CHROMIUM_LINKER)
    public static boolean sUseLinker = true;
#else
    public static boolean sUseLinker = false;
#endif

#if defined(ENABLE_CHROMIUM_LINKER_LIBRARY_IN_ZIP_FILE)
    public static boolean sUseLibraryInZipFile = true;
#else
    public static boolean sUseLibraryInZipFile = false;
#endif

#if defined(ENABLE_CHROMIUM_LINKER_TESTS)
    public static boolean sEnableLinkerTests = true;
#else
    public static boolean sEnableLinkerTests = false;
#endif

    // This is the list of native libraries to be loaded (in the correct order)
    // by LibraryLoader.java.  The base java library is compiled with no
    // array defined, and then the build system creates a version of the file
    // with the real list of libraries required (which changes based upon which
    // .apk is being built).
    // TODO(cjhopman): This is public since it is referenced by NativeTestActivity.java
    // directly. The two ways of library loading should be refactored into one.
    public static final String[] LIBRARIES =
#if defined(NATIVE_LIBRARIES_LIST)
      NATIVE_LIBRARIES_LIST;
#else
      {};
#endif

    // This is the expected version of the 'main' native library, which is the one that
    // implements the initial set of base JNI functions including
    // base::android::nativeGetVersionName()
    static String sVersionNumber =
#if defined(NATIVE_LIBRARIES_VERSION_NUMBER)
      NATIVE_LIBRARIES_VERSION_NUMBER;
#else
      "";
#endif
}