/*
 * Copyright (C) 2015 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
 */

package com.android.server.pm;

import android.annotation.Nullable;
import android.content.Context;
import android.content.pm.ApplicationInfo;
import android.content.pm.PackageParser;
import android.os.PowerManager;
import android.os.UserHandle;
import android.os.WorkSource;
import android.util.ArraySet;
import android.util.Log;
import android.util.Slog;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

import dalvik.system.DexFile;

import static com.android.server.pm.InstructionSets.getAppDexInstructionSets;
import static com.android.server.pm.InstructionSets.getDexCodeInstructionSets;

/**
 * Helper class for running dexopt command on packages.
 */
final class PackageDexOptimizer {
    private static final String TAG = "PackageManager.DexOptimizer";
    static final String OAT_DIR_NAME = "oat";
    // TODO b/19550105 Remove error codes and use exceptions
    static final int DEX_OPT_SKIPPED = 0;
    static final int DEX_OPT_PERFORMED = 1;
    static final int DEX_OPT_DEFERRED = 2;
    static final int DEX_OPT_FAILED = -1;

    private final PackageManagerService mPackageManagerService;
    private ArraySet<PackageParser.Package> mDeferredDexOpt;

    private final PowerManager.WakeLock mDexoptWakeLock;
    private volatile boolean mSystemReady;

    PackageDexOptimizer(PackageManagerService packageManagerService) {
        this.mPackageManagerService = packageManagerService;
        PowerManager powerManager = (PowerManager)packageManagerService.mContext.getSystemService(
                Context.POWER_SERVICE);
        mDexoptWakeLock = powerManager.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK, "*dexopt*");
    }

    /**
     * Performs dexopt on all code paths and libraries of the specified package for specified
     * instruction sets.
     *
     * <p>Calls to {@link com.android.server.pm.Installer#dexopt} are synchronized on
     * {@link PackageManagerService#mInstallLock}.
     */
    int performDexOpt(PackageParser.Package pkg, String[] instructionSets,
            boolean forceDex, boolean defer, boolean inclDependencies) {
        ArraySet<String> done;
        if (inclDependencies && (pkg.usesLibraries != null || pkg.usesOptionalLibraries != null)) {
            done = new ArraySet<String>();
            done.add(pkg.packageName);
        } else {
            done = null;
        }
        synchronized (mPackageManagerService.mInstallLock) {
            final boolean useLock = mSystemReady;
            if (useLock) {
                mDexoptWakeLock.setWorkSource(new WorkSource(pkg.applicationInfo.uid));
                mDexoptWakeLock.acquire();
            }
            try {
                return performDexOptLI(pkg, instructionSets, forceDex, defer, done);
            } finally {
                if (useLock) {
                    mDexoptWakeLock.release();
                }
            }
        }
    }

    private int performDexOptLI(PackageParser.Package pkg, String[] targetInstructionSets,
            boolean forceDex, boolean defer, ArraySet<String> done) {
        final String[] instructionSets = targetInstructionSets != null ?
                targetInstructionSets : getAppDexInstructionSets(pkg.applicationInfo);

        if (done != null) {
            done.add(pkg.packageName);
            if (pkg.usesLibraries != null) {
                performDexOptLibsLI(pkg.usesLibraries, instructionSets, forceDex, defer, done);
            }
            if (pkg.usesOptionalLibraries != null) {
                performDexOptLibsLI(pkg.usesOptionalLibraries, instructionSets, forceDex, defer,
                        done);
            }
        }

        if ((pkg.applicationInfo.flags & ApplicationInfo.FLAG_HAS_CODE) == 0) {
            return DEX_OPT_SKIPPED;
        }

        final boolean vmSafeMode = (pkg.applicationInfo.flags & ApplicationInfo.FLAG_VM_SAFE_MODE) != 0;
        final boolean debuggable = (pkg.applicationInfo.flags & ApplicationInfo.FLAG_DEBUGGABLE) != 0;

        final List<String> paths = pkg.getAllCodePathsExcludingResourceOnly();
        boolean performedDexOpt = false;
        // There are three basic cases here:
        // 1.) we need to dexopt, either because we are forced or it is needed
        // 2.) we are deferring a needed dexopt
        // 3.) we are skipping an unneeded dexopt
        final String[] dexCodeInstructionSets = getDexCodeInstructionSets(instructionSets);
        for (String dexCodeInstructionSet : dexCodeInstructionSets) {
            if (!forceDex && pkg.mDexOptPerformed.contains(dexCodeInstructionSet)) {
                continue;
            }

            for (String path : paths) {
                final int dexoptNeeded;
                if (forceDex) {
                    dexoptNeeded = DexFile.DEX2OAT_NEEDED;
                } else {
                    try {
                        dexoptNeeded = DexFile.getDexOptNeeded(path, pkg.packageName,
                                dexCodeInstructionSet, defer);
                    } catch (IOException ioe) {
                        Slog.w(TAG, "IOException reading apk: " + path, ioe);
                        return DEX_OPT_FAILED;
                    }
                }

                if (!forceDex && defer && dexoptNeeded != DexFile.NO_DEXOPT_NEEDED) {
                    // We're deciding to defer a needed dexopt. Don't bother dexopting for other
                    // paths and instruction sets. We'll deal with them all together when we process
                    // our list of deferred dexopts.
                    addPackageForDeferredDexopt(pkg);
                    return DEX_OPT_DEFERRED;
                }

                if (dexoptNeeded != DexFile.NO_DEXOPT_NEEDED) {
                    final String dexoptType;
                    String oatDir = null;
                    if (dexoptNeeded == DexFile.DEX2OAT_NEEDED) {
                        dexoptType = "dex2oat";
                        try {
                            oatDir = createOatDirIfSupported(pkg, dexCodeInstructionSet);
                        } catch (IOException ioe) {
                            Slog.w(TAG, "Unable to create oatDir for package: " + pkg.packageName);
                            return DEX_OPT_FAILED;
                        }
                    } else if (dexoptNeeded == DexFile.PATCHOAT_NEEDED) {
                        dexoptType = "patchoat";
                    } else if (dexoptNeeded == DexFile.SELF_PATCHOAT_NEEDED) {
                        dexoptType = "self patchoat";
                    } else {
                        throw new IllegalStateException("Invalid dexopt needed: " + dexoptNeeded);
                    }

                    Log.i(TAG, "Running dexopt (" + dexoptType + ") on: " + path + " pkg="
                            + pkg.applicationInfo.packageName + " isa=" + dexCodeInstructionSet
                            + " vmSafeMode=" + vmSafeMode + " debuggable=" + debuggable
                            + " oatDir = " + oatDir);
                    final int sharedGid = UserHandle.getSharedAppGid(pkg.applicationInfo.uid);
                    final int ret = mPackageManagerService.mInstaller.dexopt(path, sharedGid,
                            !pkg.isForwardLocked(), pkg.packageName, dexCodeInstructionSet,
                            dexoptNeeded, vmSafeMode, debuggable, oatDir);

                    // Dex2oat might fail due to compiler / verifier errors. We soldier on
                    // regardless, and attempt to interpret the app as a safety net.
                    if (ret == 0) {
                        performedDexOpt = true;
                    }
                }
            }

            // At this point we haven't failed dexopt and we haven't deferred dexopt. We must
            // either have either succeeded dexopt, or have had getDexOptNeeded tell us
            // it isn't required. We therefore mark that this package doesn't need dexopt unless
            // it's forced. performedDexOpt will tell us whether we performed dex-opt or skipped
            // it.
            pkg.mDexOptPerformed.add(dexCodeInstructionSet);
        }

        // If we've gotten here, we're sure that no error occurred and that we haven't
        // deferred dex-opt. We've either dex-opted one more paths or instruction sets or
        // we've skipped all of them because they are up to date. In both cases this
        // package doesn't need dexopt any longer.
        return performedDexOpt ? DEX_OPT_PERFORMED : DEX_OPT_SKIPPED;
    }

    /**
     * Creates oat dir for the specified package. In certain cases oat directory
     * <strong>cannot</strong> be created:
     * <ul>
     *      <li>{@code pkg} is a system app, which is not updated.</li>
     *      <li>Package location is not a directory, i.e. monolithic install.</li>
     * </ul>
     *
     * @return Absolute path to the oat directory or null, if oat directory
     * cannot be created.
     */
    @Nullable
    private String createOatDirIfSupported(PackageParser.Package pkg, String dexInstructionSet)
            throws IOException {
        if (!pkg.canHaveOatDir()) {
            return null;
        }
        File codePath = new File(pkg.codePath);
        if (codePath.isDirectory()) {
            File oatDir = getOatDir(codePath);
            mPackageManagerService.mInstaller.createOatDir(oatDir.getAbsolutePath(),
                    dexInstructionSet);
            return oatDir.getAbsolutePath();
        }
        return null;
    }

    static File getOatDir(File codePath) {
        return new File(codePath, OAT_DIR_NAME);
    }

    private void performDexOptLibsLI(ArrayList<String> libs, String[] instructionSets,
            boolean forceDex, boolean defer, ArraySet<String> done) {
        for (String libName : libs) {
            PackageParser.Package libPkg = mPackageManagerService.findSharedNonSystemLibrary(
                    libName);
            if (libPkg != null && !done.contains(libName)) {
                performDexOptLI(libPkg, instructionSets, forceDex, defer, done);
            }
        }
    }

    /**
     * Clears set of deferred dexopt packages.
     * @return content of dexopt set if it was not empty
     */
    public ArraySet<PackageParser.Package> clearDeferredDexOptPackages() {
        ArraySet<PackageParser.Package> result = mDeferredDexOpt;
        mDeferredDexOpt = null;
        return result;
    }

    public void addPackageForDeferredDexopt(PackageParser.Package pkg) {
        if (mDeferredDexOpt == null) {
            mDeferredDexOpt = new ArraySet<>();
        }
        mDeferredDexOpt.add(pkg);
    }

    void systemReady() {
        mSystemReady = true;
    }
}