android.util.AtomicFile#finishWrite ( )源码实例Demo

@Override
protected void writeInternal(Void data) {
    AtomicFile file = getFile();
    FileOutputStream f = null;

    try {
        f = file.startWrite();
        OutputStreamWriter osw = new OutputStreamWriter(f);
        write(osw);
        osw.flush();
        file.finishWrite(f);
    } catch (IOException e) {
        if (f != null) {
            file.failWrite(f);
        }
        Slog.e(TAG, "Failed to write usage for dex files", e);
    }
}
 

private void writeUserLP(UserData userData) {
    if (DBG) {
        debug("writeUserLP " + userData);
    }
    FileOutputStream fos = null;
    AtomicFile userFile = new AtomicFile(new File(mUsersDir, userData.info.id + XML_SUFFIX));
    try {
        fos = userFile.startWrite();
        final BufferedOutputStream bos = new BufferedOutputStream(fos);
        writeUserLP(userData, bos);
        userFile.finishWrite(fos);
    } catch (Exception ioe) {
        Slog.e(LOG_TAG, "Error writing user info " + userData.info.id, ioe);
        userFile.failWrite(fos);
    }
}
 

@VisibleForTesting
@GuardedBy("mAppRestrictionsLock")
static void writeApplicationRestrictionsLAr(Bundle restrictions, AtomicFile restrictionsFile) {
    FileOutputStream fos = null;
    try {
        fos = restrictionsFile.startWrite();
        final BufferedOutputStream bos = new BufferedOutputStream(fos);

        final XmlSerializer serializer = new FastXmlSerializer();
        serializer.setOutput(bos, StandardCharsets.UTF_8.name());
        serializer.startDocument(null, true);
        serializer.setFeature("http://xmlpull.org/v1/doc/features.html#indent-output", true);

        serializer.startTag(null, TAG_RESTRICTIONS);
        writeBundle(restrictions, serializer);
        serializer.endTag(null, TAG_RESTRICTIONS);

        serializer.endDocument();
        restrictionsFile.finishWrite(fos);
    } catch (Exception e) {
        restrictionsFile.failWrite(fos);
        Slog.e(LOG_TAG, "Error writing application restrictions list", e);
    }
}
 

@Override
protected void writeInternal(Void data) {
    AtomicFile file = getFile();
    FileOutputStream f = null;

    try {
        f = file.startWrite();
        OutputStreamWriter osw = new OutputStreamWriter(f);
        write(osw);
        osw.flush();
        file.finishWrite(f);
    } catch (IOException e) {
        if (f != null) {
            file.failWrite(f);
        }
        Log.e(PackageManagerService.TAG, "Failed to write compiler stats", e);
    }
}
 

@GuardedBy("mLock")
private void saveUserLocked(@UserIdInt int userId) {
    final File path = getUserFile(userId);
    if (DEBUG) {
        Slog.d(TAG, "Saving to " + path);
    }

    mShortcutBitmapSaver.waitForAllSavesLocked();

    path.getParentFile().mkdirs();
    final AtomicFile file = new AtomicFile(path);
    FileOutputStream os = null;
    try {
        os = file.startWrite();

        saveUserInternalLocked(userId, os, /* forBackup= */ false);

        file.finishWrite(os);

        // Remove all dangling bitmap files.
        cleanupDanglingBitmapDirectoriesLocked(userId);
    } catch (XmlPullParserException | IOException e) {
        Slog.e(TAG, "Failed to write to file " + file.getBaseFile(), e);
        file.failWrite(os);
    }
}
 

private void writeEvents() {
    synchronized (mEventsLock) {
        if (!mEventsDirty) {
            // Nothing to write
            return;
        }

        final AtomicFile writeTo = mInjector.getFile(EVENTS_FILE);
        if (writeTo == null) {
            return;
        }
        if (mEvents.isEmpty()) {
            if (writeTo.exists()) {
                writeTo.delete();
            }
            mEventsDirty = false;
        } else {
            FileOutputStream output = null;
            try {
                output = writeTo.startWrite();
                writeEventsLocked(output);
                writeTo.finishWrite(output);
                mEventsDirty = false;
            } catch (IOException e) {
                writeTo.failWrite(output);
                Slog.e(TAG, "Failed to write change mEvents.", e);
            }
        }
    }
}
 

private void writeAmbientBrightnessStats() {
    final AtomicFile writeTo = mInjector.getFile(AMBIENT_BRIGHTNESS_STATS_FILE);
    if (writeTo == null) {
        return;
    }
    FileOutputStream output = null;
    try {
        output = writeTo.startWrite();
        mAmbientBrightnessStatsTracker.writeStats(output);
        writeTo.finishWrite(output);
    } catch (IOException e) {
        writeTo.failWrite(output);
        Slog.e(TAG, "Failed to write ambient brightness stats.", e);
    }
}
 

@GuardedBy("mLock")
private void saveDefaultValuesLocked() {
    final AtomicFile file = new AtomicFile(injectDefaultValuesFilename());

    FileOutputStream outs = null;
    try {
        file.getBaseFile().getParentFile().mkdirs();
        outs = file.startWrite();

        // Write to XML
        XmlSerializer out = new FastXmlSerializer();
        out.setOutput(outs, StandardCharsets.UTF_8.name());
        out.startDocument(null, true);
        out.startTag(null, TAG_DEFAULT_ROOT);

        XmlUtils.writeMapXml(mDefaultValues, out, null);

        // Epilogue.
        out.endTag(null, TAG_DEFAULT_ROOT);
        out.endDocument();

        // Close.
        file.finishWrite(outs);
    } catch (IOException | XmlPullParserException | RuntimeException e) {
        Slog.e(TAG, "Failed to write to file " + file.getBaseFile(), e);
        file.failWrite(outs);
    }
}
 

@Override
protected void writeInternal(Map<String, PackageParser.Package> packages) {
    AtomicFile file = getFile();
    FileOutputStream f = null;
    try {
        f = file.startWrite();
        BufferedOutputStream out = new BufferedOutputStream(f);
        FileUtils.setPermissions(file.getBaseFile().getPath(),
                0640, SYSTEM_UID, PACKAGE_INFO_GID);
        StringBuilder sb = new StringBuilder();

        sb.append(USAGE_FILE_MAGIC_VERSION_1);
        sb.append('\n');
        out.write(sb.toString().getBytes(StandardCharsets.US_ASCII));

        for (PackageParser.Package pkg : packages.values()) {
            if (pkg.getLatestPackageUseTimeInMills() == 0L) {
                continue;
            }
            sb.setLength(0);
            sb.append(pkg.packageName);
            for (long usageTimeInMillis : pkg.mLastPackageUsageTimeInMills) {
                sb.append(' ');
                sb.append(usageTimeInMillis);
            }
            sb.append('\n');
            out.write(sb.toString().getBytes(StandardCharsets.US_ASCII));
        }
        out.flush();
        file.finishWrite(f);
    } catch (IOException e) {
        if (f != null) {
            file.failWrite(f);
        }
        Log.e(PackageManagerService.TAG, "Failed to write package usage times", e);
    }
}
 

@GuardedBy("mLock")
@VisibleForTesting
void saveBaseStateLocked() {
    final AtomicFile file = getBaseStateFile();
    if (DEBUG) {
        Slog.d(TAG, "Saving to " + file.getBaseFile());
    }

    FileOutputStream outs = null;
    try {
        outs = file.startWrite();

        // Write to XML
        XmlSerializer out = new FastXmlSerializer();
        out.setOutput(outs, StandardCharsets.UTF_8.name());
        out.startDocument(null, true);
        out.startTag(null, TAG_ROOT);

        // Body.
        writeTagValue(out, TAG_LAST_RESET_TIME, mRawLastResetTime);

        // Epilogue.
        out.endTag(null, TAG_ROOT);
        out.endDocument();

        // Close.
        file.finishWrite(outs);
    } catch (IOException e) {
        Slog.e(TAG, "Failed to write to file " + file.getBaseFile(), e);
        file.failWrite(outs);
    }
}
 

void performWriteState(long initialTime) {
    if (DEBUG) Slog.d(TAG, "Performing write to " + mFile.getBaseFile());
    Parcel data;
    AtomicFile file;
    synchronized (mPendingWriteLock) {
        data = mPendingWrite;
        file = mPendingWriteFile;
        mPendingWriteCommitted = false;
        if (data == null) {
            return;
        }
        mPendingWrite = null;
        mPendingWriteFile = null;
        mWriteLock.lock();
    }

    final long startTime = SystemClock.uptimeMillis();
    FileOutputStream stream = null;
    try {
        stream = file.startWrite();
        stream.write(data.marshall());
        stream.flush();
        file.finishWrite(stream);
        com.android.internal.logging.EventLogTags.writeCommitSysConfigFile(
                "procstats", SystemClock.uptimeMillis() - startTime + initialTime);
        if (DEBUG) Slog.d(TAG, "Write completed successfully!");
    } catch (IOException e) {
        Slog.w(TAG, "Error writing process statistics", e);
        file.failWrite(stream);
    } finally {
        data.recycle();
        trimHistoricStatesWriteLocked();
        mWriteLock.unlock();
    }
}
 

/**
 * Writes services of a specified user to the file.
 */
private void writePersistentServicesLocked(UserServices<V> user, int userId) {
    if (mSerializerAndParser == null) {
        return;
    }
    AtomicFile atomicFile = createFileForUser(userId);
    FileOutputStream fos = null;
    try {
        fos = atomicFile.startWrite();
        XmlSerializer out = new FastXmlSerializer();
        out.setOutput(fos, StandardCharsets.UTF_8.name());
        out.startDocument(null, true);
        out.setFeature("http://xmlpull.org/v1/doc/features.html#indent-output", true);
        out.startTag(null, "services");
        for (Map.Entry<V, Integer> service : user.persistentServices.entrySet()) {
            out.startTag(null, "service");
            out.attribute(null, "uid", Integer.toString(service.getValue()));
            mSerializerAndParser.writeAsXml(service.getKey(), out);
            out.endTag(null, "service");
        }
        out.endTag(null, "services");
        out.endDocument();
        atomicFile.finishWrite(fos);
    } catch (IOException e1) {
        Log.w(TAG, "Error writing accounts", e1);
        if (fos != null) {
            atomicFile.failWrite(fos);
        }
    }
}
 

private void doWriteState() {
    AtomicFile destination = new AtomicFile(mFile);

    ArrayList<Fingerprint> fingerprints;

    synchronized (this) {
        fingerprints = getCopy(mFingerprints);
    }

    FileOutputStream out = null;
    try {
        out = destination.startWrite();

        XmlSerializer serializer = Xml.newSerializer();
        serializer.setOutput(out, "utf-8");
        serializer.setFeature("http://xmlpull.org/v1/doc/features.html#indent-output", true);
        serializer.startDocument(null, true);
        serializer.startTag(null, TAG_FINGERPRINTS);

        final int count = fingerprints.size();
        for (int i = 0; i < count; i++) {
            Fingerprint fp = fingerprints.get(i);
            serializer.startTag(null, TAG_FINGERPRINT);
            serializer.attribute(null, ATTR_FINGER_ID, Integer.toString(fp.getFingerId()));
            serializer.attribute(null, ATTR_NAME, fp.getName().toString());
            serializer.attribute(null, ATTR_GROUP_ID, Integer.toString(fp.getGroupId()));
            serializer.attribute(null, ATTR_DEVICE_ID, Long.toString(fp.getDeviceId()));
            serializer.endTag(null, TAG_FINGERPRINT);
        }

        serializer.endTag(null, TAG_FINGERPRINTS);
        serializer.endDocument();
        destination.finishWrite(out);

        // Any error while writing is fatal.
    } catch (Throwable t) {
        Slog.wtf(TAG, "Failed to write settings, restoring backup", t);
        destination.failWrite(out);
        throw new IllegalStateException("Failed to write fingerprints", t);
    } finally {
        IoUtils.closeQuietly(out);
    }
}
 

private void writeUninstalledInstantAppMetadata(
        @NonNull InstantAppInfo instantApp, @UserIdInt int userId) {
    File appDir = getInstantApplicationDir(instantApp.getPackageName(), userId);
    if (!appDir.exists() && !appDir.mkdirs()) {
        return;
    }

    File metadataFile = new File(appDir, INSTANT_APP_METADATA_FILE);

    AtomicFile destination = new AtomicFile(metadataFile);
    FileOutputStream out = null;
    try {
        out = destination.startWrite();

        XmlSerializer serializer = Xml.newSerializer();
        serializer.setOutput(out, StandardCharsets.UTF_8.name());
        serializer.setFeature("http://xmlpull.org/v1/doc/features.html#indent-output", true);

        serializer.startDocument(null, true);

        serializer.startTag(null, TAG_PACKAGE);
        serializer.attribute(null, ATTR_LABEL, instantApp.loadLabel(
                mService.mContext.getPackageManager()).toString());

        serializer.startTag(null, TAG_PERMISSIONS);
        for (String permission : instantApp.getRequestedPermissions()) {
            serializer.startTag(null, TAG_PERMISSION);
            serializer.attribute(null, ATTR_NAME, permission);
            if (ArrayUtils.contains(instantApp.getGrantedPermissions(), permission)) {
                serializer.attribute(null, ATTR_GRANTED, String.valueOf(true));
            }
            serializer.endTag(null, TAG_PERMISSION);
        }
        serializer.endTag(null, TAG_PERMISSIONS);

        serializer.endTag(null, TAG_PACKAGE);

        serializer.endDocument();
        destination.finishWrite(out);
    } catch (Throwable t) {
        Slog.wtf(LOG_TAG, "Failed to write instant state, restoring backup", t);
        destination.failWrite(out);
    } finally {
        IoUtils.closeQuietly(out);
    }
}
 

private static void writeAdditionalInputMethodSubtypes(
        HashMap<String, List<InputMethodSubtype>> allSubtypes, AtomicFile subtypesFile,
        HashMap<String, InputMethodInfo> methodMap) {
    // Safety net for the case that this function is called before methodMap is set.
    final boolean isSetMethodMap = methodMap != null && methodMap.size() > 0;
    FileOutputStream fos = null;
    try {
        fos = subtypesFile.startWrite();
        final XmlSerializer out = new FastXmlSerializer();
        out.setOutput(fos, "utf-8");
        out.startDocument(null, true);
        out.setFeature("http://xmlpull.org/v1/doc/features.html#indent-output", true);
        out.startTag(null, NODE_SUBTYPES);
        for (String imiId : allSubtypes.keySet()) {
            if (isSetMethodMap && !methodMap.containsKey(imiId)) {
                Slog.w(TAG, "IME uninstalled or not valid.: " + imiId);
                continue;
            }
            out.startTag(null, NODE_IMI);
            out.attribute(null, ATTR_ID, imiId);
            final List<InputMethodSubtype> subtypesList = allSubtypes.get(imiId);
            final int N = subtypesList.size();
            for (int i = 0; i < N; ++i) {
                final InputMethodSubtype subtype = subtypesList.get(i);
                out.startTag(null, NODE_SUBTYPE);
                out.attribute(null, ATTR_ICON, String.valueOf(subtype.getIconResId()));
                out.attribute(null, ATTR_LABEL, String.valueOf(subtype.getNameResId()));
                out.attribute(null, ATTR_IME_SUBTYPE_LOCALE, subtype.getLocale());
                out.attribute(null, ATTR_IME_SUBTYPE_MODE, subtype.getMode());
                out.attribute(null, ATTR_IME_SUBTYPE_EXTRA_VALUE, subtype.getExtraValue());
                out.attribute(null, ATTR_IS_AUXILIARY,
                        String.valueOf(subtype.isAuxiliary() ? 1 : 0));
                out.endTag(null, NODE_SUBTYPE);
            }
            out.endTag(null, NODE_IMI);
        }
        out.endTag(null, NODE_SUBTYPES);
        out.endDocument();
        subtypesFile.finishWrite(fos);
    } catch (IOException e) {
        Slog.w(TAG, "Error writing subtypes", e);
        if (fos != null) {
            subtypesFile.failWrite(fos);
        }
    }
}
 

private void doWriteState() {
    boolean wroteState = false;
    final int version;
    final ArrayMap<String, Setting> settings;

    synchronized (mLock) {
        version = mVersion;
        settings = new ArrayMap<>(mSettings);
        mDirty = false;
        mWriteScheduled = false;
    }

    synchronized (mWriteLock) {
        if (DEBUG_PERSISTENCE) {
            Slog.i(LOG_TAG, "[PERSIST START]");
        }

        AtomicFile destination = new AtomicFile(mStatePersistFile);
        FileOutputStream out = null;
        try {
            out = destination.startWrite();

            XmlSerializer serializer = Xml.newSerializer();
            serializer.setOutput(out, StandardCharsets.UTF_8.name());
            serializer.setFeature("http://xmlpull.org/v1/doc/features.html#indent-output",
                    true);
            serializer.startDocument(null, true);
            serializer.startTag(null, TAG_SETTINGS);
            serializer.attribute(null, ATTR_VERSION, String.valueOf(version));

            final int settingCount = settings.size();
            for (int i = 0; i < settingCount; i++) {
                Setting setting = settings.valueAt(i);

                writeSingleSetting(mVersion, serializer, setting.getId(), setting.getName(),
                        setting.getValue(), setting.getDefaultValue(), setting.getPackageName(),
                        setting.getTag(), setting.isDefaultFromSystem());

                if (DEBUG_PERSISTENCE) {
                    Slog.i(LOG_TAG, "[PERSISTED]" + setting.getName() + "="
                            + setting.getValue());
                }
            }

            serializer.endTag(null, TAG_SETTINGS);
            serializer.endDocument();
            destination.finishWrite(out);

            wroteState = true;

            if (DEBUG_PERSISTENCE) {
                Slog.i(LOG_TAG, "[PERSIST END]");
            }
        } catch (Throwable t) {
            Slog.wtf(LOG_TAG, "Failed to write settings, restoring backup", t);
            destination.failWrite(out);
        } finally {
            IoUtils.closeQuietly(out);
        }
    }

    if (wroteState) {
        synchronized (mLock) {
            addHistoricalOperationLocked(HISTORICAL_OPERATION_PERSIST, null);
        }
    }
}