Merge "Move codes generating html file from xml files to SettingsLib (2/2)"
diff --git a/packages/SettingsLib/src/com/android/settingslib/license/LicenseHtmlGeneratorFromXml.java b/packages/SettingsLib/src/com/android/settingslib/license/LicenseHtmlGeneratorFromXml.java
new file mode 100644
index 0000000..e3e27ce1
--- /dev/null
+++ b/packages/SettingsLib/src/com/android/settingslib/license/LicenseHtmlGeneratorFromXml.java
@@ -0,0 +1,292 @@
+/*
+ * Copyright (C) 2017 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.settingslib.license;
+
+import android.support.annotation.VisibleForTesting;
+import android.text.TextUtils;
+import android.util.Log;
+import android.util.Xml;
+
+import org.xmlpull.v1.XmlPullParser;
+import org.xmlpull.v1.XmlPullParserException;
+
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.FileNotFoundException;
+import java.io.FileReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.io.PrintWriter;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.zip.GZIPInputStream;
+
+/**
+ * The utility class that generate a license html file from xml files.
+ * All the HTML snippets and logic are copied from build/make/tools/generate-notice-files.py.
+ *
+ * TODO: Remove duplicate codes once backward support ends.
+ */
+class LicenseHtmlGeneratorFromXml {
+    private static final String TAG = "LicenseHtmlGeneratorFromXml";
+
+    private static final String TAG_ROOT = "licenses";
+    private static final String TAG_FILE_NAME = "file-name";
+    private static final String TAG_FILE_CONTENT = "file-content";
+    private static final String ATTR_CONTENT_ID = "contentId";
+
+    private static final String HTML_HEAD_STRING =
+            "<html><head>\n"
+            + "<style type=\"text/css\">\n"
+            + "body { padding: 0; font-family: sans-serif; }\n"
+            + ".same-license { background-color: #eeeeee;\n"
+            + "                border-top: 20px solid white;\n"
+            + "                padding: 10px; }\n"
+            + ".label { font-weight: bold; }\n"
+            + ".file-list { margin-left: 1em; color: blue; }\n"
+            + "</style>\n"
+            + "</head>"
+            + "<body topmargin=\"0\" leftmargin=\"0\" rightmargin=\"0\" bottommargin=\"0\">\n"
+            + "<div class=\"toc\">\n"
+            + "<ul>";
+
+    private static final String HTML_MIDDLE_STRING =
+            "</ul>\n"
+            + "</div><!-- table of contents -->\n"
+            + "<table cellpadding=\"0\" cellspacing=\"0\" border=\"0\">";
+
+    private static final String HTML_REAR_STRING =
+            "</table></body></html>";
+
+    private final List<File> mXmlFiles;
+
+    /*
+     * A map from a file name to a content id (MD5 sum of file content) for its license.
+     * For example, "/system/priv-app/TeleService/TeleService.apk" maps to
+     * "9645f39e9db895a4aa6e02cb57294595". Here "9645f39e9db895a4aa6e02cb57294595" is a MD5 sum
+     * of the content of packages/services/Telephony/MODULE_LICENSE_APACHE2.
+     */
+    private final Map<String, String> mFileNameToContentIdMap = new HashMap();
+
+    /*
+     * A map from a content id (MD5 sum of file content) to a license file content.
+     * For example, "9645f39e9db895a4aa6e02cb57294595" maps to the content string of
+     * packages/services/Telephony/MODULE_LICENSE_APACHE2. Here "9645f39e9db895a4aa6e02cb57294595"
+     * is a MD5 sum of the file content.
+     */
+    private final Map<String, String> mContentIdToFileContentMap = new HashMap();
+
+    static class ContentIdAndFileNames {
+        final String mContentId;
+        final List<String> mFileNameList = new ArrayList();
+
+        ContentIdAndFileNames(String contentId) {
+            mContentId = contentId;
+        }
+    }
+
+    private LicenseHtmlGeneratorFromXml(List<File> xmlFiles) {
+        mXmlFiles = xmlFiles;
+    }
+
+    public static boolean generateHtml(List<File> xmlFiles, File outputFile) {
+        LicenseHtmlGeneratorFromXml genertor = new LicenseHtmlGeneratorFromXml(xmlFiles);
+        return genertor.generateHtml(outputFile);
+    }
+
+    private boolean generateHtml(File outputFile) {
+        for (File xmlFile : mXmlFiles) {
+            parse(xmlFile);
+        }
+
+        if (mFileNameToContentIdMap.isEmpty() || mContentIdToFileContentMap.isEmpty()) {
+            return false;
+        }
+
+        PrintWriter writer = null;
+        try {
+            writer = new PrintWriter(outputFile);
+
+            generateHtml(mFileNameToContentIdMap, mContentIdToFileContentMap, writer);
+
+            writer.flush();
+            writer.close();
+            return true;
+        } catch (FileNotFoundException | SecurityException e) {
+            Log.e(TAG, "Failed to generate " + outputFile, e);
+
+            if (writer != null) {
+                writer.close();
+            }
+            return false;
+        }
+    }
+
+    private void parse(File xmlFile) {
+        if (xmlFile == null || !xmlFile.exists() || xmlFile.length() == 0) {
+            return;
+        }
+
+        InputStreamReader in = null;
+        try {
+            if (xmlFile.getName().endsWith(".gz")) {
+                in = new InputStreamReader(new GZIPInputStream(new FileInputStream(xmlFile)));
+            } else {
+                in = new FileReader(xmlFile);
+            }
+
+            parse(in, mFileNameToContentIdMap, mContentIdToFileContentMap);
+
+            in.close();
+        } catch (XmlPullParserException | IOException e) {
+            Log.e(TAG, "Failed to parse " + xmlFile, e);
+            if (in != null) {
+                try {
+                    in.close();
+                } catch (IOException ie) {
+                    Log.w(TAG, "Failed to close " + xmlFile);
+                }
+            }
+        }
+    }
+
+    /*
+     * Parses an input stream and fills a map from a file name to a content id for its license
+     * and a map from a content id to a license file content.
+     *
+     * Following xml format is expected from the input stream.
+     *
+     *     <licenses>
+     *     <file-name contentId="content_id_of_license1">file1</file-name>
+     *     <file-name contentId="content_id_of_license2">file2</file-name>
+     *     ...
+     *     <file-content contentId="content_id_of_license1">license1 file contents</file-content>
+     *     <file-content contentId="content_id_of_license2">license2 file contents</file-content>
+     *     ...
+     *     </licenses>
+     */
+    @VisibleForTesting
+    static void parse(InputStreamReader in, Map<String, String> outFileNameToContentIdMap,
+            Map<String, String> outContentIdToFileContentMap)
+                    throws XmlPullParserException, IOException {
+        Map<String, String> fileNameToContentIdMap = new HashMap<String, String>();
+        Map<String, String> contentIdToFileContentMap = new HashMap<String, String>();
+
+        XmlPullParser parser = Xml.newPullParser();
+        parser.setInput(in);
+        parser.nextTag();
+
+        parser.require(XmlPullParser.START_TAG, "", TAG_ROOT);
+
+        int state = parser.getEventType();
+        while (state != XmlPullParser.END_DOCUMENT) {
+            if (state == XmlPullParser.START_TAG) {
+                if (TAG_FILE_NAME.equals(parser.getName())) {
+                    String contentId = parser.getAttributeValue("", ATTR_CONTENT_ID);
+                    if (!TextUtils.isEmpty(contentId)) {
+                        String fileName = readText(parser).trim();
+                        if (!TextUtils.isEmpty(fileName)) {
+                            fileNameToContentIdMap.put(fileName, contentId);
+                        }
+                    }
+                } else if (TAG_FILE_CONTENT.equals(parser.getName())) {
+                    String contentId = parser.getAttributeValue("", ATTR_CONTENT_ID);
+                    if (!TextUtils.isEmpty(contentId)
+                            && !outContentIdToFileContentMap.containsKey(contentId)
+                            && !contentIdToFileContentMap.containsKey(contentId)) {
+                        String fileContent = readText(parser);
+                        if (!TextUtils.isEmpty(fileContent)) {
+                            contentIdToFileContentMap.put(contentId, fileContent);
+                        }
+                    }
+                }
+            }
+
+            state = parser.next();
+        }
+        outFileNameToContentIdMap.putAll(fileNameToContentIdMap);
+        outContentIdToFileContentMap.putAll(contentIdToFileContentMap);
+    }
+
+    private static String readText(XmlPullParser parser)
+            throws IOException, XmlPullParserException {
+        StringBuffer result = new StringBuffer();
+        int state = parser.next();
+        while (state == XmlPullParser.TEXT) {
+            result.append(parser.getText());
+            state = parser.next();
+        }
+        return result.toString();
+    }
+
+    @VisibleForTesting
+    static void generateHtml(Map<String, String> fileNameToContentIdMap,
+            Map<String, String> contentIdToFileContentMap, PrintWriter writer) {
+        List<String> fileNameList = new ArrayList();
+        fileNameList.addAll(fileNameToContentIdMap.keySet());
+        Collections.sort(fileNameList);
+
+        writer.println(HTML_HEAD_STRING);
+
+        int count = 0;
+        Map<String, Integer> contentIdToOrderMap = new HashMap();
+        List<ContentIdAndFileNames> contentIdAndFileNamesList = new ArrayList();
+
+        // Prints all the file list with a link to its license file content.
+        for (String fileName : fileNameList) {
+            String contentId = fileNameToContentIdMap.get(fileName);
+            // Assigns an id to a newly referred license file content.
+            if (!contentIdToOrderMap.containsKey(contentId)) {
+                contentIdToOrderMap.put(contentId, count);
+
+                // An index in contentIdAndFileNamesList is the order of each element.
+                contentIdAndFileNamesList.add(new ContentIdAndFileNames(contentId));
+                count++;
+            }
+
+            int id = contentIdToOrderMap.get(contentId);
+            contentIdAndFileNamesList.get(id).mFileNameList.add(fileName);
+            writer.format("<li><a href=\"#id%d\">%s</a></li>\n", id, fileName);
+        }
+
+        writer.println(HTML_MIDDLE_STRING);
+
+        count = 0;
+        // Prints all contents of the license files in order of id.
+        for (ContentIdAndFileNames contentIdAndFileNames : contentIdAndFileNamesList) {
+            writer.format("<tr id=\"id%d\"><td class=\"same-license\">\n", count);
+            writer.println("<div class=\"label\">Notices for file(s):</div>");
+            writer.println("<div class=\"file-list\">");
+            for (String fileName : contentIdAndFileNames.mFileNameList) {
+                writer.format("%s <br/>\n", fileName);
+            }
+            writer.println("</div><!-- file-list -->");
+            writer.println("<pre class=\"license-text\">");
+            writer.println(contentIdToFileContentMap.get(
+                    contentIdAndFileNames.mContentId));
+            writer.println("</pre><!-- license-text -->");
+            writer.println("</td></tr><!-- same-license -->");
+
+            count++;
+        }
+
+        writer.println(HTML_REAR_STRING);
+    }
+}
diff --git a/packages/SettingsLib/src/com/android/settingslib/license/LicenseHtmlLoader.java b/packages/SettingsLib/src/com/android/settingslib/license/LicenseHtmlLoader.java
new file mode 100644
index 0000000..a9fb20c
--- /dev/null
+++ b/packages/SettingsLib/src/com/android/settingslib/license/LicenseHtmlLoader.java
@@ -0,0 +1,110 @@
+/*
+ * Copyright (C) 2017 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.settingslib.license;
+
+import android.content.Context;
+import android.support.annotation.VisibleForTesting;
+import android.util.Log;
+
+import com.android.settingslib.utils.AsyncLoader;
+
+import java.io.File;
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * LicenseHtmlLoader is a loader which loads a license html file from default license xml files.
+ */
+public class LicenseHtmlLoader extends AsyncLoader<File> {
+    private static final String TAG = "LicenseHtmlLoader";
+
+    private static final String[] DEFAULT_LICENSE_XML_PATHS = {
+            "/system/etc/NOTICE.xml.gz",
+            "/vendor/etc/NOTICE.xml.gz",
+            "/odm/etc/NOTICE.xml.gz",
+            "/oem/etc/NOTICE.xml.gz"};
+    private static final String NOTICE_HTML_FILE_NAME = "NOTICE.html";
+
+    private Context mContext;
+
+    public LicenseHtmlLoader(Context context) {
+        super(context);
+        mContext = context;
+    }
+
+    @Override
+    public File loadInBackground() {
+        return generateHtmlFromDefaultXmlFiles();
+    }
+
+    @Override
+    protected void onDiscardResult(File f) {
+    }
+
+    private File generateHtmlFromDefaultXmlFiles() {
+        final List<File> xmlFiles = getVaildXmlFiles();
+        if (xmlFiles.isEmpty()) {
+            Log.e(TAG, "No notice file exists.");
+            return null;
+        }
+
+        File cachedHtmlFile = getCachedHtmlFile();
+        if (!isCachedHtmlFileOutdated(xmlFiles, cachedHtmlFile)
+                || generateHtmlFile(xmlFiles, cachedHtmlFile)) {
+            return cachedHtmlFile;
+        }
+
+        return null;
+    }
+
+    @VisibleForTesting
+    List<File> getVaildXmlFiles() {
+        final List<File> xmlFiles = new ArrayList();
+        for (final String xmlPath : DEFAULT_LICENSE_XML_PATHS) {
+            File file = new File(xmlPath);
+            if (file.exists() && file.length() != 0) {
+                xmlFiles.add(file);
+            }
+        }
+        return xmlFiles;
+    }
+
+    @VisibleForTesting
+    File getCachedHtmlFile() {
+        return new File(mContext.getCacheDir(), NOTICE_HTML_FILE_NAME);
+    }
+
+    @VisibleForTesting
+    boolean isCachedHtmlFileOutdated(List<File> xmlFiles, File cachedHtmlFile) {
+        boolean outdated = true;
+        if (cachedHtmlFile.exists() && cachedHtmlFile.length() != 0) {
+            outdated = false;
+            for (File file : xmlFiles) {
+                if (cachedHtmlFile.lastModified() < file.lastModified()) {
+                    outdated = true;
+                    break;
+                }
+            }
+        }
+        return outdated;
+    }
+
+    @VisibleForTesting
+    boolean generateHtmlFile(List<File> xmlFiles, File htmlFile) {
+        return LicenseHtmlGeneratorFromXml.generateHtml(xmlFiles, htmlFile);
+    }
+}
diff --git a/packages/SettingsLib/src/com/android/settingslib/utils/AsyncLoader.java b/packages/SettingsLib/src/com/android/settingslib/utils/AsyncLoader.java
new file mode 100644
index 0000000..06770ac
--- /dev/null
+++ b/packages/SettingsLib/src/com/android/settingslib/utils/AsyncLoader.java
@@ -0,0 +1,110 @@
+/*
+ * Copyright (C) 2017 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.settingslib.utils;
+
+import android.content.AsyncTaskLoader;
+import android.content.Context;
+
+/**
+ * This class fills in some boilerplate for AsyncTaskLoader to actually load things.
+ *
+ * Subclasses need to implement {@link AsyncLoader#loadInBackground()} to perform the actual
+ * background task, and {@link AsyncLoader#onDiscardResult(T)} to clean up previously loaded
+ * results.
+ *
+ * This loader is based on the MailAsyncTaskLoader from the AOSP EmailUnified repo.
+ *
+ * @param <T> the data type to be loaded.
+ */
+public abstract class AsyncLoader<T> extends AsyncTaskLoader<T> {
+    private T mResult;
+
+    public AsyncLoader(final Context context) {
+        super(context);
+    }
+
+    @Override
+    protected void onStartLoading() {
+        if (mResult != null) {
+            deliverResult(mResult);
+        }
+
+        if (takeContentChanged() || mResult == null) {
+            forceLoad();
+        }
+    }
+
+    @Override
+    protected void onStopLoading() {
+        cancelLoad();
+    }
+
+    @Override
+    public void deliverResult(final T data) {
+        if (isReset()) {
+            if (data != null) {
+                onDiscardResult(data);
+            }
+            return;
+        }
+
+        final T oldResult = mResult;
+        mResult = data;
+
+        if (isStarted()) {
+            super.deliverResult(data);
+        }
+
+        if (oldResult != null && oldResult != mResult) {
+            onDiscardResult(oldResult);
+        }
+    }
+
+    @Override
+    protected void onReset() {
+        super.onReset();
+
+        onStopLoading();
+
+        if (mResult != null) {
+            onDiscardResult(mResult);
+        }
+        mResult = null;
+    }
+
+    @Override
+    public void onCanceled(final T data) {
+        super.onCanceled(data);
+
+        if (data != null) {
+            onDiscardResult(data);
+        }
+    }
+
+    /**
+     * Called when discarding the load results so subclasses can take care of clean-up or
+     * recycling tasks. This is not called if the same result (by way of pointer equality) is
+     * returned again by a subsequent call to loadInBackground, or if result is null.
+     *
+     * Note that this may be called concurrently with loadInBackground(), and in some circumstances
+     * may be called more than once for a given object.
+     *
+     * @param result The value returned from {@link AsyncLoader#loadInBackground()} which
+     *               is to be discarded.
+     */
+    protected abstract void onDiscardResult(T result);
+}
diff --git a/packages/SettingsLib/tests/robotests/src/com/android/settingslib/license/LicenseHtmlGeneratorFromXmlTest.java b/packages/SettingsLib/tests/robotests/src/com/android/settingslib/license/LicenseHtmlGeneratorFromXmlTest.java
new file mode 100644
index 0000000..c7e9262
--- /dev/null
+++ b/packages/SettingsLib/tests/robotests/src/com/android/settingslib/license/LicenseHtmlGeneratorFromXmlTest.java
@@ -0,0 +1,126 @@
+/*
+ * Copyright (C) 2017 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.settingslib.license;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import com.android.settingslib.TestConfig;
+import com.android.settingslib.SettingsLibRobolectricTestRunner;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.robolectric.annotation.Config;
+import org.xmlpull.v1.XmlPullParserException;
+
+import java.io.ByteArrayInputStream;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.io.PrintWriter;
+import java.io.StringWriter;
+import java.util.HashMap;
+import java.util.Map;
+
+@RunWith(SettingsLibRobolectricTestRunner.class)
+@Config(manifest = TestConfig.MANIFEST_PATH, sdk = TestConfig.SDK_VERSION)
+public class LicenseHtmlGeneratorFromXmlTest {
+    private static final String VALILD_XML_STRING =
+            "<?xml version=\"1.0\" encoding=\"utf-8\"?>\n"
+            + "<licenses>\n"
+            + "<file-name contentId=\"0\">/file0</file-name>\n"
+            + "<file-name contentId=\"0\">/file1</file-name>\n"
+            + "<file-content contentId=\"0\"><![CDATA[license content #0]]></file-content>\n"
+            + "</licenses>";
+
+    private static final String INVALILD_XML_STRING =
+            "<?xml version=\"1.0\" encoding=\"utf-8\"?>\n"
+            + "<licenses2>\n"
+            + "<file-name contentId=\"0\">/file0</file-name>\n"
+            + "<file-name contentId=\"0\">/file1</file-name>\n"
+            + "<file-content contentId=\"0\"><![CDATA[license content #0]]></file-content>\n"
+            + "</licenses2>";
+
+    private static final String EXPECTED_HTML_STRING =
+            "<html><head>\n"
+            + "<style type=\"text/css\">\n"
+            + "body { padding: 0; font-family: sans-serif; }\n"
+            + ".same-license { background-color: #eeeeee;\n"
+            + "                border-top: 20px solid white;\n"
+            + "                padding: 10px; }\n"
+            + ".label { font-weight: bold; }\n"
+            + ".file-list { margin-left: 1em; color: blue; }\n"
+            + "</style>\n"
+            + "</head>"
+            + "<body topmargin=\"0\" leftmargin=\"0\" rightmargin=\"0\" bottommargin=\"0\">\n"
+            + "<div class=\"toc\">\n"
+            + "<ul>\n"
+            + "<li><a href=\"#id0\">/file0</a></li>\n"
+            + "<li><a href=\"#id0\">/file1</a></li>\n"
+            + "</ul>\n"
+            + "</div><!-- table of contents -->\n"
+            + "<table cellpadding=\"0\" cellspacing=\"0\" border=\"0\">\n"
+            + "<tr id=\"id0\"><td class=\"same-license\">\n"
+            + "<div class=\"label\">Notices for file(s):</div>\n"
+            + "<div class=\"file-list\">\n"
+            + "/file0 <br/>\n"
+            + "/file1 <br/>\n"
+            + "</div><!-- file-list -->\n"
+            + "<pre class=\"license-text\">\n"
+            + "license content #0\n"
+            + "</pre><!-- license-text -->\n"
+            + "</td></tr><!-- same-license -->\n"
+            + "</table></body></html>\n";
+
+    @Test
+    public void testParseValidXmlStream() throws XmlPullParserException, IOException {
+        Map<String, String> fileNameToContentIdMap = new HashMap<String, String>();
+        Map<String, String> contentIdToFileContentMap = new HashMap<String, String>();
+
+        LicenseHtmlGeneratorFromXml.parse(
+                new InputStreamReader(new ByteArrayInputStream(VALILD_XML_STRING.getBytes())),
+                fileNameToContentIdMap, contentIdToFileContentMap);
+        assertThat(fileNameToContentIdMap.size()).isEqualTo(2);
+        assertThat(fileNameToContentIdMap.get("/file0")).isEqualTo("0");
+        assertThat(fileNameToContentIdMap.get("/file1")).isEqualTo("0");
+        assertThat(contentIdToFileContentMap.size()).isEqualTo(1);
+        assertThat(contentIdToFileContentMap.get("0")).isEqualTo("license content #0");
+    }
+
+    @Test(expected = XmlPullParserException.class)
+    public void testParseInvalidXmlStream() throws XmlPullParserException, IOException {
+        Map<String, String> fileNameToContentIdMap = new HashMap<String, String>();
+        Map<String, String> contentIdToFileContentMap = new HashMap<String, String>();
+
+        LicenseHtmlGeneratorFromXml.parse(
+                new InputStreamReader(new ByteArrayInputStream(INVALILD_XML_STRING.getBytes())),
+                fileNameToContentIdMap, contentIdToFileContentMap);
+    }
+
+    @Test
+    public void testGenerateHtml() {
+        Map<String, String> fileNameToContentIdMap = new HashMap<String, String>();
+        Map<String, String> contentIdToFileContentMap = new HashMap<String, String>();
+
+        fileNameToContentIdMap.put("/file0", "0");
+        fileNameToContentIdMap.put("/file1", "0");
+        contentIdToFileContentMap.put("0", "license content #0");
+
+        StringWriter output = new StringWriter();
+        LicenseHtmlGeneratorFromXml.generateHtml(
+                fileNameToContentIdMap, contentIdToFileContentMap, new PrintWriter(output));
+        assertThat(output.toString()).isEqualTo(EXPECTED_HTML_STRING);
+    }
+}
diff --git a/packages/SettingsLib/tests/robotests/src/com/android/settingslib/license/LicenseHtmlLoaderTest.java b/packages/SettingsLib/tests/robotests/src/com/android/settingslib/license/LicenseHtmlLoaderTest.java
new file mode 100644
index 0000000..1a6f30c
--- /dev/null
+++ b/packages/SettingsLib/tests/robotests/src/com/android/settingslib/license/LicenseHtmlLoaderTest.java
@@ -0,0 +1,110 @@
+/*
+ * Copyright (C) 2017 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.settingslib.license;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import static org.mockito.Matchers.any;
+import static org.mockito.Mockito.doReturn;
+import static org.mockito.Mockito.never;
+import static org.mockito.Mockito.spy;
+import static org.mockito.Mockito.verify;
+
+import android.content.Context;
+
+import com.android.settingslib.TestConfig;
+import com.android.settingslib.SettingsLibRobolectricTestRunner;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Mock;
+import org.mockito.MockitoAnnotations;
+import org.robolectric.annotation.Config;
+
+import java.io.File;
+import java.util.ArrayList;
+
+@RunWith(SettingsLibRobolectricTestRunner.class)
+@Config(manifest = TestConfig.MANIFEST_PATH, sdk = TestConfig.SDK_VERSION)
+public class LicenseHtmlLoaderTest {
+    @Mock
+    private Context mContext;
+
+    LicenseHtmlLoader newLicenseHtmlLoader(ArrayList<File> xmlFiles,
+            File cachedHtmlFile, boolean isCachedHtmlFileOutdated,
+            boolean generateHtmlFileSucceeded) {
+        LicenseHtmlLoader loader = spy(new LicenseHtmlLoader(mContext));
+        doReturn(xmlFiles).when(loader).getVaildXmlFiles();
+        doReturn(cachedHtmlFile).when(loader).getCachedHtmlFile();
+        doReturn(isCachedHtmlFileOutdated).when(loader).isCachedHtmlFileOutdated(any(), any());
+        doReturn(generateHtmlFileSucceeded).when(loader).generateHtmlFile(any(), any());
+        return loader;
+    }
+
+    @Before
+    public void setUp() {
+        MockitoAnnotations.initMocks(this);
+    }
+
+    @Test
+    public void testLoadInBackground() {
+        ArrayList<File> xmlFiles = new ArrayList();
+        xmlFiles.add(new File("test.xml"));
+        File cachedHtmlFile = new File("test.html");
+
+        LicenseHtmlLoader loader = newLicenseHtmlLoader(xmlFiles, cachedHtmlFile, true, true);
+
+        assertThat(loader.loadInBackground()).isEqualTo(cachedHtmlFile);
+        verify(loader).generateHtmlFile(any(), any());
+    }
+
+    @Test
+    public void testLoadInBackgroundWithNoVaildXmlFiles() {
+        ArrayList<File> xmlFiles = new ArrayList();
+        File cachedHtmlFile = new File("test.html");
+
+        LicenseHtmlLoader loader = newLicenseHtmlLoader(xmlFiles, cachedHtmlFile, true, true);
+
+        assertThat(loader.loadInBackground()).isNull();
+        verify(loader, never()).generateHtmlFile(any(), any());
+    }
+
+    @Test
+    public void testLoadInBackgroundWithNonOutdatedCachedHtmlFile() {
+        ArrayList<File> xmlFiles = new ArrayList();
+        xmlFiles.add(new File("test.xml"));
+        File cachedHtmlFile = new File("test.html");
+
+        LicenseHtmlLoader loader = newLicenseHtmlLoader(xmlFiles, cachedHtmlFile, false, true);
+
+        assertThat(loader.loadInBackground()).isEqualTo(cachedHtmlFile);
+        verify(loader, never()).generateHtmlFile(any(), any());
+    }
+
+    @Test
+    public void testLoadInBackgroundWithGenerateHtmlFileFailed() {
+        ArrayList<File> xmlFiles = new ArrayList();
+        xmlFiles.add(new File("test.xml"));
+        File cachedHtmlFile = new File("test.html");
+
+        LicenseHtmlLoader loader = newLicenseHtmlLoader(xmlFiles, cachedHtmlFile, true, false);
+
+        assertThat(loader.loadInBackground()).isNull();
+        verify(loader).generateHtmlFile(any(), any());
+    }
+}
diff --git a/services/core/java/com/android/server/am/ActivityManagerService.java b/services/core/java/com/android/server/am/ActivityManagerService.java
index 2ca2c27..7b4703a 100644
--- a/services/core/java/com/android/server/am/ActivityManagerService.java
+++ b/services/core/java/com/android/server/am/ActivityManagerService.java
@@ -8877,7 +8877,10 @@
         final int callingAppId = UserHandle.getAppId(callingUid);
         if ((callingAppId == SYSTEM_UID) || (callingAppId == ROOT_UID)) {
             if ("com.android.settings.files".equals(grantUri.uri.getAuthority())) {
-                // Exempted authority for cropping user photos in Settings app
+                // Exempted authority for
+                // 1. cropping user photos and sharing a generated license html
+                //    file in Settings app
+                // 2. sharing a generated license html file in TvSettings app
             } else {
                 Slog.w(TAG, "For security reasons, the system cannot issue a Uri permission"
                         + " grant to " + grantUri + "; use startActivityAsCaller() instead");