Cronet API Refactoring

components/cronet/android/api/src/org/chromium/net/UserAgent.java

-// 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.net;
-
-import android.content.Context;
-import android.content.pm.PackageInfo;
-import android.content.pm.PackageManager;
-import android.content.pm.PackageManager.NameNotFoundException;
-import android.os.Build;
-
-import java.util.Locale;
-
-/**
- * Constructs a User-Agent string.
- */
-final class UserAgent {
-    private static final Object sLock = new Object();
-
-    private static final int VERSION_CODE_UNINITIALIZED = 0;
-    private static int sVersionCode = VERSION_CODE_UNINITIALIZED;
-
-    private UserAgent() {
-    }
-
-    /**
-     * Constructs a User-Agent string including application name and version,
-     * system build version, model and Id, and Cronet version.
-     * @param context the context to fetch the application name and version
-     *         from.
-     * @return User-Agent string.
-     */
-    public static String from(Context context) {
-        StringBuilder builder = new StringBuilder();
-
-        // Our package name and version.
-        builder.append(context.getPackageName());
-        builder.append('/');
-        builder.append(versionFromContext(context));
-
-        // The platform version.
-        builder.append(" (Linux; U; Android ");
-        builder.append(Build.VERSION.RELEASE);
-        builder.append("; ");
-        builder.append(Locale.getDefault().toString());
-
-        String model = Build.MODEL;
-        if (model.length() > 0) {
-            builder.append("; ");
-            builder.append(model);
-        }
-
-        String id = Build.ID;
-        if (id.length() > 0) {
-            builder.append("; Build/");
-            builder.append(id);
-        }
-
-        builder.append(";");
-        appendCronetVersion(builder);
-
-        builder.append(')');
-
-        return builder.toString();
-    }
-
-    /**
-     * Constructs default QUIC User Agent Id string including application name
-     * and Cronet version.
-     * @param context the context to fetch the application name from.
-     * @return User-Agent string.
-     */
-    static String getQuicUserAgentIdFrom(Context context) {
-        StringBuilder builder = new StringBuilder();
-
-        // Application name and cronet version.
-        builder.append(context.getPackageName());
-        appendCronetVersion(builder);
-
-        return builder.toString();
-    }
-
-    private static int versionFromContext(Context context) {
-        synchronized (sLock) {
-            if (sVersionCode == VERSION_CODE_UNINITIALIZED) {
-                PackageManager packageManager = context.getPackageManager();
-                String packageName = context.getPackageName();
-                try {
-                    PackageInfo packageInfo = packageManager.getPackageInfo(
-                            packageName, 0);
-                    sVersionCode = packageInfo.versionCode;
-                } catch (NameNotFoundException e) {
-                    throw new IllegalStateException(
-                            "Cannot determine package version");
-                }
-            }
-            return sVersionCode;
-        }
-    }
-
-    private static void appendCronetVersion(StringBuilder builder) {
-        builder.append(" Cronet/");
-        // TODO(pauljensen): This is the API version not the implementation
-        // version. The implementation version may be more appropriate for the
-        // UserAgent but is not available until after the CronetEngine is
-        // instantiated. Down the road, if the implementation is loaded via
-        // other means, this should be replaced with the implementation version.
-        builder.append(ApiVersion.CRONET_VERSION);
-    }
-}