1 files changed, 122 insertions, 0 deletions
diff --git a/src/com/android/tv/license/Licenses.java b/src/com/android/tv/license/Licenses.java
new file mode 100644
index 00000000..4b8a7ffc
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+++ b/src/com/android/tv/license/Licenses.java
@@ -0,0 +1,122 @@
+/*
+ * 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.tv.license;
+
+import android.content.Context;
+import android.support.annotation.RawRes;
+
+import com.android.tv.R;
+import com.android.tv.common.SoftPreconditions;
+
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.UnsupportedEncodingException;
+import java.util.ArrayList;
+import java.util.Collections;
+
+/**
+ * A helper for extracting licenses embedded using
+ * third_party_licenses.build:third_party_licenses().
+ */
+public final class Licenses {
+
+    public static final String TAG = "Licenses";
+    public static boolean hasLicenses(Context context) {
+        return !getTextFromResource(
+                        context.getApplicationContext(), R.raw.third_party_license_metadata, 0, -1)
+                .isEmpty();
+    }
+
+    /** Return the licenses bundled into this app. */
+    public static ArrayList<License> getLicenses(Context context) {
+        return getLicenseListFromMetadata(
+                getTextFromResource(
+                        context.getApplicationContext(), R.raw.third_party_license_metadata, 0, -1),
+                "");
+    }
+
+    /**
+     * Returns a list of {@link License}s parsed from a license metadata file.
+     *
+     * @param metadata a {@code String} containing the contents of a license metadata file.
+     * @param filePath a path to a package archive with licenses or empty string for the app package
+     */
+    private static ArrayList<License> getLicenseListFromMetadata(String metadata, String filePath) {
+        String[] entries = metadata.split("\n");
+        ArrayList<License> licenses = new ArrayList<License>(entries.length);
+        for (String entry : entries) {
+            int delimiter = entry.indexOf(' ');
+            String[] licenseLocation = entry.substring(0, delimiter).split(":");
+            SoftPreconditions.checkState(
+                    licenseLocation.length == 2 && delimiter > 0,
+                    TAG,
+                    "Invalid license meta-data line:\n" + entry);
+            long licenseOffset = Long.parseLong(licenseLocation[0]);
+            int licenseLength = Integer.parseInt(licenseLocation[1]);
+            licenses.add(
+                    License.create(
+                            entry.substring(delimiter + 1),
+                            licenseOffset,
+                            licenseLength,
+                            filePath));
+        }
+        Collections.sort(licenses);
+        return licenses;
+    }
+
+    /** Return the text of a bundled license file. */
+    public static String getLicenseText(Context context, License license) {
+        long offset = license.getLicenseOffset();
+        int length = license.getLicenseLength();
+        return getTextFromResource(context, R.raw.third_party_licenses, offset, length);
+    }
+
+    private static String getTextFromResource(
+            Context context, @RawRes int resourcesIdentifier, long offset, int length) {
+        InputStream stream =
+                context.getApplicationContext().getResources().openRawResource(resourcesIdentifier);
+        return getTextFromInputStream(stream, offset, length);
+    }
+
+    private static String getTextFromInputStream(InputStream stream, long offset, int length) {
+        byte[] buffer = new byte[1024];
+        ByteArrayOutputStream textArray = new ByteArrayOutputStream();
+
+        try {
+            stream.skip(offset);
+            int bytesRemaining = length > 0 ? length : Integer.MAX_VALUE;
+            int bytes = 0;
+
+            while (bytesRemaining > 0
+                    && (bytes = stream.read(buffer, 0, Math.min(bytesRemaining, buffer.length)))
+                            != -1) {
+                textArray.write(buffer, 0, bytes);
+                bytesRemaining -= bytes;
+            }
+            stream.close();
+        } catch (IOException e) {
+            throw new RuntimeException("Failed to read license or metadata text.", e);
+        }
+        try {
+            return textArray.toString("UTF-8");
+        } catch (UnsupportedEncodingException e) {
+            throw new RuntimeException(
+                    "Unsupported encoding UTF8. This should always be supported.", e);
+        }
+    }
+}