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A framework for building native apps with React
/**
* Copyright (c) 2015-present, Facebook, Inc.
* All rights reserved.
*
* This source code is licensed under the BSD-style license found in the
* LICENSE file in the root directory of this source tree. An additional grant
* of patent rights can be found in the PATENTS file in the same directory.
*/
package com.facebook.react.bridge;
import javax.annotation.Nullable;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.HashMap;
import java.util.Map;
import com.facebook.infer.annotation.Assertions;
import com.facebook.systrace.Systrace;
import com.facebook.systrace.SystraceMessage;
import static com.facebook.infer.annotation.Assertions.assertNotNull;
import static com.facebook.systrace.Systrace.TRACE_TAG_REACT_JAVA_BRIDGE;
/**
* Base class for Catalyst native modules whose implementations are written in Java. Default
* implementations for {@link #initialize} and {@link #onCatalystInstanceDestroy} are provided for
* convenience. Subclasses which override these don't need to call {@code super} in case of
* overriding those methods as implementation of those methods is empty.
*
* BaseJavaModules can be linked to Fragments' lifecycle events, {@link CatalystInstance} creation
* and destruction, by being called on the appropriate method when a life cycle event occurs.
*
* Native methods can be exposed to JS with {@link ReactMethod} annotation. Those methods may
* only use limited number of types for their arguments:
* 1/ primitives (boolean, int, float, double
* 2/ {@link String} mapped from JS string
* 3/ {@link ReadableArray} mapped from JS Array
* 4/ {@link ReadableMap} mapped from JS Object
* 5/ {@link Callback} mapped from js function and can be used only as a last parameter or in the
* case when it express success & error callback pair as two last arguments respecively.
*
* All methods exposed as native to JS with {@link ReactMethod} annotation must return
* {@code void}.
*
* Please note that it is not allowed to have multiple methods annotated with {@link ReactMethod}
* with the same name.
*/
public abstract class BaseJavaModule implements NativeModule {
// taken from Libraries/Utilities/MessageQueue.js
static final public String METHOD_TYPE_ASYNC = "async";
static final public String METHOD_TYPE_PROMISE= "promise";
static final public String METHOD_TYPE_SYNC = "sync";
private static abstract class ArgumentExtractor {
public int getJSArgumentsNeeded() {
return 1;
}
public abstract @Nullable T extractArgument(
CatalystInstance catalystInstance, ExecutorToken executorToken, ReadableNativeArray jsArguments, int atIndex);
}
static final private ArgumentExtractor ARGUMENT_EXTRACTOR_BOOLEAN =
new ArgumentExtractor() {
@Override
public Boolean extractArgument(
CatalystInstance catalystInstance, ExecutorToken executorToken, ReadableNativeArray jsArguments, int atIndex) {
return jsArguments.getBoolean(atIndex);
}
};
static final private ArgumentExtractor ARGUMENT_EXTRACTOR_DOUBLE =
new ArgumentExtractor() {
@Override
public Double extractArgument(
CatalystInstance catalystInstance, ExecutorToken executorToken, ReadableNativeArray jsArguments, int atIndex) {
return jsArguments.getDouble(atIndex);
}
};
static final private ArgumentExtractor ARGUMENT_EXTRACTOR_FLOAT =
new ArgumentExtractor() {
@Override
public Float extractArgument(
CatalystInstance catalystInstance, ExecutorToken executorToken, ReadableNativeArray jsArguments, int atIndex) {
return (float) jsArguments.getDouble(atIndex);
}
};
static final private ArgumentExtractor ARGUMENT_EXTRACTOR_INTEGER =
new ArgumentExtractor() {
@Override
public Integer extractArgument(
CatalystInstance catalystInstance, ExecutorToken executorToken, ReadableNativeArray jsArguments, int atIndex) {
return (int) jsArguments.getDouble(atIndex);
}
};
static final private ArgumentExtractor ARGUMENT_EXTRACTOR_STRING =
new ArgumentExtractor() {
@Override
public String extractArgument(
CatalystInstance catalystInstance, ExecutorToken executorToken, ReadableNativeArray jsArguments, int atIndex) {
return jsArguments.getString(atIndex);
}
};
static final private ArgumentExtractor ARGUMENT_EXTRACTOR_ARRAY =
new ArgumentExtractor() {
@Override
public ReadableNativeArray extractArgument(
CatalystInstance catalystInstance, ExecutorToken executorToken, ReadableNativeArray jsArguments, int atIndex) {
return jsArguments.getArray(atIndex);
}
};
static final private ArgumentExtractor ARGUMENT_EXTRACTOR_MAP =
new ArgumentExtractor() {
@Override
public ReadableMap extractArgument(
CatalystInstance catalystInstance, ExecutorToken executorToken, ReadableNativeArray jsArguments, int atIndex) {
return jsArguments.getMap(atIndex);
}
};
static final private ArgumentExtractor ARGUMENT_EXTRACTOR_CALLBACK =
new ArgumentExtractor() {
@Override
public @Nullable Callback extractArgument(
CatalystInstance catalystInstance, ExecutorToken executorToken, ReadableNativeArray jsArguments, int atIndex) {
if (jsArguments.isNull(atIndex)) {
return null;
} else {
int id = (int) jsArguments.getDouble(atIndex);
return new CallbackImpl(catalystInstance, executorToken, id);
}
}
};
static final private ArgumentExtractor ARGUMENT_EXTRACTOR_PROMISE =
new ArgumentExtractor() {
@Override
public int getJSArgumentsNeeded() {
return 2;
}
@Override
public Promise extractArgument(
CatalystInstance catalystInstance, ExecutorToken executorToken, ReadableNativeArray jsArguments, int atIndex) {
Callback resolve = ARGUMENT_EXTRACTOR_CALLBACK
.extractArgument(catalystInstance, executorToken, jsArguments, atIndex);
Callback reject = ARGUMENT_EXTRACTOR_CALLBACK
.extractArgument(catalystInstance, executorToken, jsArguments, atIndex + 1);
return new PromiseImpl(resolve, reject);
}
};
public class JavaMethod implements NativeMethod {
private Method mMethod;
private final ArgumentExtractor[] mArgumentExtractors;
private final String mSignature;
private final Object[] mArguments;
private String mType = METHOD_TYPE_ASYNC;
private final int mJSArgumentsNeeded;
private final String mTraceName;
public JavaMethod(Method method) {
mMethod = method;
Class[] parameterTypes = method.getParameterTypes();
mArgumentExtractors = buildArgumentExtractors(parameterTypes);
mSignature = buildSignature(parameterTypes);
// Since native methods are invoked from a message queue executed on a single thread, it is
// save to allocate only one arguments object per method that can be reused across calls
mArguments = new Object[parameterTypes.length];
mJSArgumentsNeeded = calculateJSArgumentsNeeded();
mTraceName = BaseJavaModule.this.getName() + "." + mMethod.getName();
}
public Method getMethod() {
return mMethod;
}
public String getSignature() {
return mSignature;
}
private String buildSignature(Class[] paramTypes) {
StringBuilder builder = new StringBuilder(paramTypes.length);
builder.append("v.");
for (int i = 0; i < paramTypes.length; i++) {
Class paramClass = paramTypes[i];
if (paramClass == ExecutorToken.class) {
if (!BaseJavaModule.this.supportsWebWorkers()) {
throw new RuntimeException(
"Module " + BaseJavaModule.this + " doesn't support web workers, but " +
mMethod.getName() +
" takes an ExecutorToken.");
}
} else if (paramClass == Promise.class) {
Assertions.assertCondition(
i == paramTypes.length - 1, "Promise must be used as last parameter only");
mType = METHOD_TYPE_PROMISE;
}
builder.append(paramTypeToChar(paramClass));
}
// Modules that support web workers are expected to take an ExecutorToken as the first
// parameter to all their @ReactMethod-annotated methods.
if (BaseJavaModule.this.supportsWebWorkers()) {
if (builder.charAt(2) != 'T') {
throw new RuntimeException(
"Module " + BaseJavaModule.this + " supports web workers, but " + mMethod.getName() +
"does not take an ExecutorToken as its first parameter.");
}
}
return builder.toString();
}
private ArgumentExtractor[] buildArgumentExtractors(Class[] paramTypes) {
// Modules that support web workers are expected to take an ExecutorToken as the first
// parameter to all their @ReactMethod-annotated methods. We compensate for that here.
int executorTokenOffset = 0;
if (BaseJavaModule.this.supportsWebWorkers()) {
if (paramTypes[0] != ExecutorToken.class) {
throw new RuntimeException(
"Module " + BaseJavaModule.this + " supports web workers, but " + mMethod.getName() +
"does not take an ExecutorToken as its first parameter.");
}
executorTokenOffset = 1;
}
ArgumentExtractor[] argumentExtractors = new ArgumentExtractor[paramTypes.length - executorTokenOffset];
for (int i = 0; i < paramTypes.length - executorTokenOffset; i += argumentExtractors[i].getJSArgumentsNeeded()) {
int paramIndex = i + executorTokenOffset;
Class argumentClass = paramTypes[paramIndex];
if (argumentClass == Boolean.class || argumentClass == boolean.class) {
argumentExtractors[i] = ARGUMENT_EXTRACTOR_BOOLEAN;
} else if (argumentClass == Integer.class || argumentClass == int.class) {
argumentExtractors[i] = ARGUMENT_EXTRACTOR_INTEGER;
} else if (argumentClass == Double.class || argumentClass == double.class) {
argumentExtractors[i] = ARGUMENT_EXTRACTOR_DOUBLE;
} else if (argumentClass == Float.class || argumentClass == float.class) {
argumentExtractors[i] = ARGUMENT_EXTRACTOR_FLOAT;
} else if (argumentClass == String.class) {
argumentExtractors[i] = ARGUMENT_EXTRACTOR_STRING;
} else if (argumentClass == Callback.class) {
argumentExtractors[i] = ARGUMENT_EXTRACTOR_CALLBACK;
} else if (argumentClass == Promise.class) {
argumentExtractors[i] = ARGUMENT_EXTRACTOR_PROMISE;
Assertions.assertCondition(
paramIndex == paramTypes.length - 1, "Promise must be used as last parameter only");
mType = METHOD_TYPE_PROMISE;
} else if (argumentClass == ReadableMap.class) {
argumentExtractors[i] = ARGUMENT_EXTRACTOR_MAP;
} else if (argumentClass == ReadableArray.class) {
argumentExtractors[i] = ARGUMENT_EXTRACTOR_ARRAY;
} else {
throw new RuntimeException(
"Got unknown argument class: " + argumentClass.getSimpleName());
}
}
return argumentExtractors;
}
private int calculateJSArgumentsNeeded() {
int n = 0;
for (ArgumentExtractor extractor : mArgumentExtractors) {
n += extractor.getJSArgumentsNeeded();
}
return n;
}
private String getAffectedRange(int startIndex, int jsArgumentsNeeded) {
return jsArgumentsNeeded > 1 ?
"" + startIndex + "-" + (startIndex + jsArgumentsNeeded - 1) : "" + startIndex;
}
@Override
public void invoke(CatalystInstance catalystInstance, ExecutorToken executorToken, ReadableNativeArray parameters) {
SystraceMessage.beginSection(TRACE_TAG_REACT_JAVA_BRIDGE, "callJavaModuleMethod")
.arg("method", mTraceName)
.flush();
try {
if (mJSArgumentsNeeded != parameters.size()) {
throw new NativeArgumentsParseException(
BaseJavaModule.this.getName() + "." + mMethod.getName() + " got " +
parameters.size() + " arguments, expected " + mJSArgumentsNeeded);
}
// Modules that support web workers are expected to take an ExecutorToken as the first
// parameter to all their @ReactMethod-annotated methods. We compensate for that here.
int i = 0, jsArgumentsConsumed = 0;
int executorTokenOffset = 0;
if (BaseJavaModule.this.supportsWebWorkers()) {
mArguments[0] = executorToken;
executorTokenOffset = 1;
}
try {
for (; i < mArgumentExtractors.length; i++) {
mArguments[i + executorTokenOffset] = mArgumentExtractors[i].extractArgument(
catalystInstance, executorToken, parameters, jsArgumentsConsumed);
jsArgumentsConsumed += mArgumentExtractors[i].getJSArgumentsNeeded();
}
} catch (UnexpectedNativeTypeException e) {
throw new NativeArgumentsParseException(
e.getMessage() + " (constructing arguments for " + BaseJavaModule.this.getName() +
"." + mMethod.getName() + " at argument index " +
getAffectedRange(jsArgumentsConsumed, mArgumentExtractors[i].getJSArgumentsNeeded()) +
")",
e);
}
try {
mMethod.invoke(BaseJavaModule.this, mArguments);
} catch (IllegalArgumentException ie) {
throw new RuntimeException(
"Could not invoke " + BaseJavaModule.this.getName() + "." + mMethod.getName(), ie);
} catch (IllegalAccessException iae) {
throw new RuntimeException(
"Could not invoke " + BaseJavaModule.this.getName() + "." + mMethod.getName(), iae);
} catch (InvocationTargetException ite) {
// Exceptions thrown from native module calls end up wrapped in InvocationTargetException
// which just make traces harder to read and bump out useful information
if (ite.getCause() instanceof RuntimeException) {
throw (RuntimeException) ite.getCause();
}
throw new RuntimeException(
"Could not invoke " + BaseJavaModule.this.getName() + "." + mMethod.getName(), ite);
}
} finally {
Systrace.endSection(TRACE_TAG_REACT_JAVA_BRIDGE);
}
}
/**
* Determines how the method is exported in JavaScript:
* METHOD_TYPE_ASYNC for regular methods
* METHOD_TYPE_PROMISE for methods that return a promise object to the caller.
*/
@Override
public String getType() {
return mType;
}
}
public class SyncJavaHook implements SyncNativeHook {
private Method mMethod;
private final String mSignature;
public SyncJavaHook(Method method) {
mMethod = method;
mSignature = buildSignature(method);
}
public Method getMethod() {
return mMethod;
}
public String getSignature() {
return mSignature;
}
private String buildSignature(Method method) {
Class[] paramTypes = method.getParameterTypes();
StringBuilder builder = new StringBuilder(paramTypes.length + 2);
builder.append(returnTypeToChar(method.getReturnType()));
builder.append('.');
for (int i = 0; i < paramTypes.length; i++) {
Class paramClass = paramTypes[i];
if (paramClass == ExecutorToken.class) {
if (!BaseJavaModule.this.supportsWebWorkers()) {
throw new RuntimeException(
"Module " + BaseJavaModule.this + " doesn't support web workers, but " +
mMethod.getName() +
" takes an ExecutorToken.");
}
} else if (paramClass == Promise.class) {
Assertions.assertCondition(
i == paramTypes.length - 1, "Promise must be used as last parameter only");
}
builder.append(paramTypeToChar(paramClass));
}
return builder.toString();
}
}
private @Nullable Map mMethods;
private @Nullable Map mHooks;
private void findMethods() {
if (mMethods == null) {
Systrace.beginSection(TRACE_TAG_REACT_JAVA_BRIDGE, "findMethods");
mMethods = new HashMap<>();
mHooks = new HashMap<>();
Method[] targetMethods = getClass().getDeclaredMethods();
for (Method targetMethod : targetMethods) {
if (targetMethod.getAnnotation(ReactMethod.class) != null) {
String methodName = targetMethod.getName();
if (mHooks.containsKey(methodName) || mMethods.containsKey(methodName)) {
// We do not support method overloading since js sees a function as an object regardless
// of number of params.
throw new IllegalArgumentException(
"Java Module " + getName() + " sync method name already registered: " + methodName);
}
mMethods.put(methodName, new JavaMethod(targetMethod));
}
if (targetMethod.getAnnotation(ReactSyncHook.class) != null) {
String methodName = targetMethod.getName();
if (mHooks.containsKey(methodName) || mMethods.containsKey(methodName)) {
// We do not support method overloading since js sees a function as an object regardless
// of number of params.
throw new IllegalArgumentException(
"Java Module " + getName() + " sync method name already registered: " + methodName);
}
mHooks.put(methodName, new SyncJavaHook(targetMethod));
}
}
Systrace.endSection(TRACE_TAG_REACT_JAVA_BRIDGE);
}
}
@Override
public final Map getMethods() {
findMethods();
return assertNotNull(mMethods);
}
/**
* @return a map of constants this module exports to JS. Supports JSON types.
*/
public @Nullable Map getConstants() {
return null;
}
public final Map getSyncHooks() {
findMethods();
return assertNotNull(mHooks);
}
@Override
public void initialize() {
// do nothing
}
@Override
public boolean canOverrideExistingModule() {
// TODO(t11394819): Make this final and use annotation
return false;
}
@Override
public void onCatalystInstanceDestroy() {
// do nothing
}
@Override
public boolean supportsWebWorkers() {
return false;
}
private static char paramTypeToChar(Class paramClass) {
char tryCommon = commonTypeToChar(paramClass);
if (tryCommon != '\0') {
return tryCommon;
}
if (paramClass == ExecutorToken.class) {
return 'T';
} else if (paramClass == Callback.class) {
return 'X';
} else if (paramClass == Promise.class) {
return 'P';
} else if (paramClass == ReadableMap.class) {
return 'M';
} else if (paramClass == ReadableArray.class) {
return 'A';
} else {
throw new RuntimeException(
"Got unknown param class: " + paramClass.getSimpleName());
}
}
private static char returnTypeToChar(Class returnClass) {
char tryCommon = commonTypeToChar(returnClass);
if (tryCommon != '\0') {
return tryCommon;
}
if (returnClass == void.class) {
return 'v';
} else if (returnClass == WritableMap.class) {
return 'M';
} else if (returnClass == WritableArray.class) {
return 'A';
} else {
throw new RuntimeException(
"Got unknown return class: " + returnClass.getSimpleName());
}
}
private static char commonTypeToChar(Class typeClass) {
if (typeClass == boolean.class) {
return 'z';
} else if (typeClass == Boolean.class) {
return 'Z';
} else if (typeClass == int.class) {
return 'i';
} else if (typeClass == Integer.class) {
return 'I';
} else if (typeClass == double.class) {
return 'd';
} else if (typeClass == Double.class) {
return 'D';
} else if (typeClass == float.class) {
return 'f';
} else if (typeClass == Float.class) {
return 'F';
} else if (typeClass == String.class) {
return 'S';
} else {
return '\0';
}
}
}