// Copyright 2017 The Chromium Authors
// 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.util.Log;
import androidx.annotation.Nullable;
import org.chromium.net.impl.CronetLogger;
import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Set;
/**
* Provides a factory method to create {@link CronetEngine.Builder} instances. A {@code
* CronetEngine.Builder} instance can be used to create a specific {@link CronetEngine}
* implementation. To get the list of available {@link CronetProvider}s call {@link
* #getAllProviderInfos(Context)}.
*
* <p><b>NOTE:</b> This class is for advanced users that want to select a particular Cronet
* implementation. Most users should simply use {@code new} {@link
* CronetEngine.Builder#CronetEngine.Builder(android.content.Context)}.
*
* <p>{@hide}
*/
public abstract class CronetProvider {
/**
* String returned by {@link CronetProvider#getName} for {@link CronetProvider} that provides
* native Cronet implementation packaged inside an application. This implementation offers
* significantly higher performance relative to the fallback Cronet implementations (see {@link
* #PROVIDER_NAME_FALLBACK}).
*/
public static final String PROVIDER_NAME_APP_PACKAGED = "App-Packaged-Cronet-Provider";
/**
* String returned by {@link CronetProvider#getName} for {@link CronetProvider} that provides
* Cronet implementation based on the system's {@link java.net.HttpURLConnection}
* implementation. This implementation offers significantly degraded performance relative to
* native Cronet implementations (see {@link #PROVIDER_NAME_APP_PACKAGED}).
*/
public static final String PROVIDER_NAME_FALLBACK = "Fallback-Cronet-Provider";
/**
* The name of an optional key in the app string resource file that contains the class name of
* an alternative {@code CronetProvider} implementation.
*/
private static final String RES_KEY_CRONET_IMPL_CLASS = "CronetProviderClassName";
private static final String TAG = CronetProvider.class.getSimpleName();
protected final Context mContext;
protected CronetProvider(Context context) {
if (context == null) {
throw new IllegalArgumentException("Context must not be null");
}
mContext = context;
}
/**
* Creates and returns an instance of {@link CronetEngine.Builder}.
* <p/>
* <b>NOTE:</b> This class is for advanced users that want to select a particular
* Cronet implementation. Most users should simply use {@code new} {@link
* CronetEngine.Builder#CronetEngine.Builder(android.content.Context)}.
*
* @return {@code CronetEngine.Builder}.
* @throws IllegalStateException if the provider is not enabled (see {@link #isEnabled}.
*/
public abstract CronetEngine.Builder createBuilder();
/**
* Returns the provider name. The well-know provider names include:
* <ul>
* <li>{@link #PROVIDER_NAME_APP_PACKAGED}</li>
* <li>{@link #PROVIDER_NAME_FALLBACK}</li>
* </ul>
*
* @return provider name.
*/
public abstract String getName();
/**
* Returns the provider version. The version can be used to select the newest available provider
* if multiple providers are available.
*
* @return provider version.
*/
public abstract String getVersion();
/**
* Returns whether the provider is enabled and can be used to instantiate the Cronet engine. A
* provider being out-of-date (older than the API) and needing updating is one potential reason
* it could be disabled. Please read the provider documentation for enablement procedure.
*
* @return {@code true} if the provider is enabled.
*/
public abstract boolean isEnabled();
@Override
public String toString() {
return "["
+ "class="
+ getClass().getName()
+ ", "
+ "name="
+ getName()
+ ", "
+ "version="
+ getVersion()
+ ", "
+ "enabled="
+ isEnabled()
+ "]";
}
/** Name of the Java {@link CronetProvider} class. */
private static final String JAVA_CRONET_PROVIDER_CLASS =
"org.chromium.net.impl.JavaCronetProvider";
/** Name of the native {@link CronetProvider} class. */
private static final String NATIVE_CRONET_PROVIDER_CLASS =
"org.chromium.net.impl.NativeCronetProvider";
/** {@link CronetProvider} class that is packaged with Google Play Services. */
private static final String PLAY_SERVICES_CRONET_PROVIDER_CLASS =
"com.google.android.gms.net.PlayServicesCronetProvider";
/**
* {@link CronetProvider} a deprecated class that may be packaged with some old versions of
* Google Play Services.
*/
private static final String GMS_CORE_CRONET_PROVIDER_CLASS =
"com.google.android.gms.net.GmsCoreCronetProvider";
static final class ProviderInfo {
public CronetProvider provider;
public CronetLogger.CronetSource logSource;
// Delegate ProviderInfo comparisons to `provider`. This actually matters in some cases such
// as PLAY_SERVICES vs GMS_CORE, see b/329440572.
@Override
public int hashCode() {
return provider.hashCode();
}
@Override
public boolean equals(@Nullable Object other) {
return other instanceof ProviderInfo
&& provider.equals(((ProviderInfo) other).provider);
}
}
/**
* Returns an unmodifiable list of all available {@link CronetProvider}s. The providers are
* returned in no particular order. Some of the returned providers may be in a disabled state
* and should be enabled by the invoker. See {@link CronetProvider#isEnabled()}.
*
* @return the list of available providers.
*/
public static List<CronetProvider> getAllProviders(Context context) {
var providers = new ArrayList<CronetProvider>();
for (var providerInfo : getAllProviderInfos(context)) {
providers.add(providerInfo.provider);
}
return Collections.unmodifiableList(providers);
}
/**
* Same as {@link #getAllProviders}, but returning the providerInfos directly.
*
* @return the list of available providerInfos.
*/
static List<ProviderInfo> getAllProviderInfos(Context context) {
// Use LinkedHashSet to preserve the order and eliminate duplicate providers.
Set<ProviderInfo> providers = new LinkedHashSet<>();
addCronetProviderFromResourceFile(
context, CronetLogger.CronetSource.CRONET_SOURCE_UNSPECIFIED, providers);
addCronetProviderImplByClassName(
context,
PLAY_SERVICES_CRONET_PROVIDER_CLASS,
CronetLogger.CronetSource.CRONET_SOURCE_PLAY_SERVICES,
providers,
false);
addCronetProviderImplByClassName(
context,
GMS_CORE_CRONET_PROVIDER_CLASS,
CronetLogger.CronetSource.CRONET_SOURCE_PLAY_SERVICES,
providers,
false);
addCronetProviderImplByClassName(
context,
NATIVE_CRONET_PROVIDER_CLASS,
CronetLogger.CronetSource.CRONET_SOURCE_STATICALLY_LINKED,
providers,
false);
addCronetProviderImplByClassName(
context,
JAVA_CRONET_PROVIDER_CLASS,
CronetLogger.CronetSource.CRONET_SOURCE_FALLBACK,
providers,
false);
return Collections.unmodifiableList(new ArrayList<>(providers));
}
/**
* Attempts to add a new provider referenced by the class name to a set.
*
* @param className the class name of the provider that should be instantiated.
* @param providers the set of providers to add the new provider to.
* @return {@code true} if the provider was added to the set; {@code false} if the provider
* couldn't be instantiated.
*/
private static boolean addCronetProviderImplByClassName(
Context context,
String className,
CronetLogger.CronetSource logSource,
Set<ProviderInfo> providers,
boolean logError) {
ClassLoader loader = context.getClassLoader();
try {
Class<? extends CronetProvider> providerClass =
loader.loadClass(className).asSubclass(CronetProvider.class);
Constructor<? extends CronetProvider> ctor =
providerClass.getConstructor(Context.class);
var providerInfo = new ProviderInfo();
providerInfo.provider = ctor.newInstance(context);
providerInfo.logSource = logSource;
providers.add(providerInfo);
return true;
} catch (InstantiationException e) {
logReflectiveOperationException(className, logError, e);
} catch (InvocationTargetException e) {
logReflectiveOperationException(className, logError, e);
} catch (NoSuchMethodException e) {
logReflectiveOperationException(className, logError, e);
} catch (IllegalAccessException e) {
logReflectiveOperationException(className, logError, e);
} catch (ClassNotFoundException e) {
logReflectiveOperationException(className, logError, e);
}
return false;
}
/**
* De-duplicates exception handling logic in {@link #addCronetProviderImplByClassName}. It
* should be removed when support of API Levels lower than 19 is deprecated.
*/
private static void logReflectiveOperationException(
String className, boolean logError, Exception e) {
if (logError) {
Log.e(TAG, "Unable to load provider class: " + className, e);
} else {
if (Log.isLoggable(TAG, Log.DEBUG)) {
Log.d(
TAG,
"Tried to load "
+ className
+ " provider class but it wasn't"
+ " included in the app classpath");
}
}
}
/**
* Attempts to add a provider specified in the app resource file to a set.
*
* @param providers the set of providers to add the new provider to.
* @return {@code true} if the provider was added to the set; {@code false} if the app resources
* do not include the string with {@link #RES_KEY_CRONET_IMPL_CLASS} key.
* @throws RuntimeException if the provider cannot be found or instantiated.
*/
// looking up resources from other apps requires the use of getIdentifier()
@SuppressWarnings("DiscouragedApi")
private static boolean addCronetProviderFromResourceFile(
Context context, CronetLogger.CronetSource logSource, Set<ProviderInfo> providers) {
int resId =
context.getResources()
.getIdentifier(
RES_KEY_CRONET_IMPL_CLASS, "string", context.getPackageName());
// Resource not found
if (resId == 0) {
// The resource wasn't included in the app; therefore, there is nothing to add.
return false;
}
String className = context.getResources().getString(resId);
// If the resource specifies a well known provider, don't load it because
// there will be an attempt to load it anyways.
if (className == null
|| className.equals(PLAY_SERVICES_CRONET_PROVIDER_CLASS)
|| className.equals(GMS_CORE_CRONET_PROVIDER_CLASS)
|| className.equals(JAVA_CRONET_PROVIDER_CLASS)
|| className.equals(NATIVE_CRONET_PROVIDER_CLASS)) {
return false;
}
if (!addCronetProviderImplByClassName(context, className, logSource, providers, true)) {
Log.e(
TAG,
"Unable to instantiate Cronet implementation class "
+ className
+ " that is listed as in the app string resource file under "
+ RES_KEY_CRONET_IMPL_CLASS
+ " key");
}
return true;
}
}
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