Update from Google.
--
MOE_MIGRATED_REVID=85702957
diff --git a/src/main/java/com/google/devtools/build/lib/syntax/FuncallExpression.java b/src/main/java/com/google/devtools/build/lib/syntax/FuncallExpression.java
new file mode 100644
index 0000000..e24d97f
--- /dev/null
+++ b/src/main/java/com/google/devtools/build/lib/syntax/FuncallExpression.java
@@ -0,0 +1,550 @@
+// Copyright 2014 Google Inc. All rights reserved.
+//
+// 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.google.devtools.build.lib.syntax;
+
+import com.google.common.base.Preconditions;
+import com.google.common.cache.CacheBuilder;
+import com.google.common.cache.CacheLoader;
+import com.google.common.cache.LoadingCache;
+import com.google.common.collect.ImmutableList;
+import com.google.common.collect.ImmutableMap;
+import com.google.common.collect.Lists;
+import com.google.devtools.build.lib.events.Location;
+import com.google.devtools.build.lib.syntax.EvalException.EvalExceptionWithJavaCause;
+import com.google.devtools.build.lib.util.StringUtilities;
+
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+import java.lang.reflect.Modifier;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.ExecutionException;
+
+/**
+ * Syntax node for a function call expression.
+ */
+public final class FuncallExpression extends Expression {
+
+ private static enum ArgConversion {
+ FROM_SKYLARK,
+ TO_SKYLARK,
+ NO_CONVERSION
+ }
+
+ /**
+ * A value class to store Methods with their corresponding SkylarkCallable annotations.
+ * This is needed because the annotation is sometimes in a superclass.
+ */
+ public static final class MethodDescriptor {
+ private final Method method;
+ private final SkylarkCallable annotation;
+
+ private MethodDescriptor(Method method, SkylarkCallable annotation) {
+ this.method = method;
+ this.annotation = annotation;
+ }
+
+ Method getMethod() {
+ return method;
+ }
+
+ /**
+ * Returns the SkylarkCallable annotation corresponding to this method.
+ */
+ public SkylarkCallable getAnnotation() {
+ return annotation;
+ }
+ }
+
+ private static final LoadingCache<Class<?>, Map<String, List<MethodDescriptor>>> methodCache =
+ CacheBuilder.newBuilder()
+ .initialCapacity(10)
+ .maximumSize(100)
+ .build(new CacheLoader<Class<?>, Map<String, List<MethodDescriptor>>>() {
+
+ @Override
+ public Map<String, List<MethodDescriptor>> load(Class<?> key) throws Exception {
+ Map<String, List<MethodDescriptor>> methodMap = new HashMap<>();
+ for (Method method : key.getMethods()) {
+ // Synthetic methods lead to false multiple matches
+ if (method.isSynthetic()) {
+ continue;
+ }
+ SkylarkCallable callable = getAnnotationFromParentClass(
+ method.getDeclaringClass(), method);
+ if (callable == null) {
+ continue;
+ }
+ String name = callable.name();
+ if (name.isEmpty()) {
+ name = StringUtilities.toPythonStyleFunctionName(method.getName());
+ }
+ String signature = name + "#" + method.getParameterTypes().length;
+ if (methodMap.containsKey(signature)) {
+ methodMap.get(signature).add(new MethodDescriptor(method, callable));
+ } else {
+ methodMap.put(signature, Lists.newArrayList(new MethodDescriptor(method, callable)));
+ }
+ }
+ return ImmutableMap.copyOf(methodMap);
+ }
+ });
+
+ /**
+ * Returns a map of methods and corresponding SkylarkCallable annotations
+ * of the methods of the classObj class reachable from Skylark.
+ */
+ public static ImmutableMap<Method, SkylarkCallable> collectSkylarkMethodsWithAnnotation(
+ Class<?> classObj) {
+ ImmutableMap.Builder<Method, SkylarkCallable> methodMap = ImmutableMap.builder();
+ for (Method method : classObj.getMethods()) {
+ // Synthetic methods lead to false multiple matches
+ if (!method.isSynthetic()) {
+ SkylarkCallable annotation = getAnnotationFromParentClass(classObj, method);
+ if (annotation != null) {
+ methodMap.put(method, annotation);
+ }
+ }
+ }
+ return methodMap.build();
+ }
+
+ private static SkylarkCallable getAnnotationFromParentClass(Class<?> classObj, Method method) {
+ boolean keepLooking = false;
+ try {
+ Method superMethod = classObj.getMethod(method.getName(), method.getParameterTypes());
+ if (classObj.isAnnotationPresent(SkylarkModule.class)
+ && superMethod.isAnnotationPresent(SkylarkCallable.class)) {
+ return superMethod.getAnnotation(SkylarkCallable.class);
+ } else {
+ keepLooking = true;
+ }
+ } catch (NoSuchMethodException e) {
+ // The class might not have the specified method, so an exceptions is OK.
+ keepLooking = true;
+ }
+ if (keepLooking) {
+ if (classObj.getSuperclass() != null) {
+ SkylarkCallable annotation = getAnnotationFromParentClass(classObj.getSuperclass(), method);
+ if (annotation != null) {
+ return annotation;
+ }
+ }
+ for (Class<?> interfaceObj : classObj.getInterfaces()) {
+ SkylarkCallable annotation = getAnnotationFromParentClass(interfaceObj, method);
+ if (annotation != null) {
+ return annotation;
+ }
+ }
+ }
+ return null;
+ }
+
+ /**
+ * An exception class to handle exceptions in direct Java API calls.
+ */
+ public static final class FuncallException extends Exception {
+
+ public FuncallException(String msg) {
+ super(msg);
+ }
+ }
+
+ private final Expression obj;
+
+ private final Ident func;
+
+ private final List<Argument> args;
+
+ private final int numPositionalArgs;
+
+ /**
+ * Note: the grammar definition restricts the function value in a function
+ * call expression to be a global identifier; however, the representation of
+ * values in the interpreter is flexible enough to allow functions to be
+ * arbitrary expressions. In any case, the "func" expression is always
+ * evaluated, so functions and variables share a common namespace.
+ */
+ public FuncallExpression(Expression obj, Ident func,
+ List<Argument> args) {
+ for (Argument arg : args) {
+ Preconditions.checkArgument(arg.hasValue());
+ }
+ this.obj = obj;
+ this.func = func;
+ this.args = args;
+ this.numPositionalArgs = countPositionalArguments();
+ }
+
+ /**
+ * Note: the grammar definition restricts the function value in a function
+ * call expression to be a global identifier; however, the representation of
+ * values in the interpreter is flexible enough to allow functions to be
+ * arbitrary expressions. In any case, the "func" expression is always
+ * evaluated, so functions and variables share a common namespace.
+ */
+ public FuncallExpression(Ident func, List<Argument> args) {
+ this(null, func, args);
+ }
+
+ /**
+ * Returns the number of positional arguments.
+ */
+ private int countPositionalArguments() {
+ int num = 0;
+ for (Argument arg : args) {
+ if (arg.isPositional()) {
+ num++;
+ }
+ }
+ return num;
+ }
+
+ /**
+ * Returns the function expression.
+ */
+ public Ident getFunction() {
+ return func;
+ }
+
+ /**
+ * Returns the object the function called on.
+ * It's null if the function is not called on an object.
+ */
+ public Expression getObject() {
+ return obj;
+ }
+
+ /**
+ * Returns an (immutable, ordered) list of function arguments. The first n are
+ * positional and the remaining ones are keyword args, where n =
+ * getNumPositionalArguments().
+ */
+ public List<Argument> getArguments() {
+ return Collections.unmodifiableList(args);
+ }
+
+ /**
+ * Returns the number of arguments which are positional; the remainder are
+ * keyword arguments.
+ */
+ public int getNumPositionalArguments() {
+ return numPositionalArgs;
+ }
+
+ @Override
+ public String toString() {
+ if (func.getName().equals("$substring")) {
+ return obj + "[" + args.get(0) + ":" + args.get(1) + "]";
+ }
+ if (func.getName().equals("$index")) {
+ return obj + "[" + args.get(0) + "]";
+ }
+ if (obj != null) {
+ return obj + "." + func + "(" + args + ")";
+ }
+ return func + "(" + args + ")";
+ }
+
+ /**
+ * Returns the list of Skylark callable Methods of objClass with the given name
+ * and argument number.
+ */
+ public static List<MethodDescriptor> getMethods(Class<?> objClass, String methodName, int argNum)
+ throws ExecutionException {
+ return methodCache.get(objClass).get(methodName + "#" + argNum);
+ }
+
+ /**
+ * Returns the list of the Skylark name of all Skylark callable methods.
+ */
+ public static List<String> getMethodNames(Class<?> objClass)
+ throws ExecutionException {
+ List<String> names = new ArrayList<>();
+ for (List<MethodDescriptor> methods : methodCache.get(objClass).values()) {
+ for (MethodDescriptor method : methods) {
+ // TODO(bazel-team): store the Skylark name in the MethodDescriptor.
+ String name = method.annotation.name();
+ if (name.isEmpty()) {
+ name = StringUtilities.toPythonStyleFunctionName(method.method.getName());
+ }
+ names.add(name);
+ }
+ }
+ return names;
+ }
+
+ static Object callMethod(MethodDescriptor methodDescriptor, String methodName, Object obj,
+ Object[] args, Location loc) throws EvalException, IllegalAccessException,
+ IllegalArgumentException, InvocationTargetException {
+ Method method = methodDescriptor.getMethod();
+ if (obj == null && !Modifier.isStatic(method.getModifiers())) {
+ throw new EvalException(loc, "Method '" + methodName + "' is not static");
+ }
+ // This happens when the interface is public but the implementation classes
+ // have reduced visibility.
+ method.setAccessible(true);
+ Object result = method.invoke(obj, args);
+ if (method.getReturnType().equals(Void.TYPE)) {
+ return Environment.NONE;
+ }
+ if (result == null) {
+ if (methodDescriptor.getAnnotation().allowReturnNones()) {
+ return Environment.NONE;
+ } else {
+ throw new EvalException(loc,
+ "Method invocation returned None, please contact Skylark developers: " + methodName
+ + "(" + EvalUtils.prettyPrintValues(", ", ImmutableList.copyOf(args)) + ")");
+ }
+ }
+ result = SkylarkType.convertToSkylark(result, method);
+ if (result != null && !EvalUtils.isSkylarkImmutable(result.getClass())) {
+ throw new EvalException(loc, "Method '" + methodName
+ + "' returns a mutable object (type of " + EvalUtils.getDatatypeName(result) + ")");
+ }
+ return result;
+ }
+
+ // TODO(bazel-team): If there's exactly one usable method, this works. If there are multiple
+ // matching methods, it still can be a problem. Figure out how the Java compiler does it
+ // exactly and copy that behaviour.
+ // TODO(bazel-team): check if this and SkylarkBuiltInFunctions.createObject can be merged.
+ private Object invokeJavaMethod(
+ Object obj, Class<?> objClass, String methodName, List<Object> args) throws EvalException {
+ try {
+ MethodDescriptor matchingMethod = null;
+ List<MethodDescriptor> methods = getMethods(objClass, methodName, args.size());
+ if (methods != null) {
+ for (MethodDescriptor method : methods) {
+ Class<?>[] params = method.getMethod().getParameterTypes();
+ int i = 0;
+ boolean matching = true;
+ for (Class<?> param : params) {
+ if (!param.isAssignableFrom(args.get(i).getClass())) {
+ matching = false;
+ break;
+ }
+ i++;
+ }
+ if (matching) {
+ if (matchingMethod == null) {
+ matchingMethod = method;
+ } else {
+ throw new EvalException(func.getLocation(),
+ "Multiple matching methods for " + formatMethod(methodName, args)
+ + " in " + EvalUtils.getDataTypeNameFromClass(objClass));
+ }
+ }
+ }
+ }
+ if (matchingMethod != null && !matchingMethod.getAnnotation().structField()) {
+ return callMethod(matchingMethod, methodName, obj, args.toArray(), getLocation());
+ } else {
+ throw new EvalException(getLocation(), "No matching method found for "
+ + formatMethod(methodName, args) + " in "
+ + EvalUtils.getDataTypeNameFromClass(objClass));
+ }
+ } catch (IllegalAccessException e) {
+ // TODO(bazel-team): Print a nice error message. Maybe the method exists
+ // and an argument is missing or has the wrong type.
+ throw new EvalException(getLocation(), "Method invocation failed: " + e);
+ } catch (InvocationTargetException e) {
+ if (e.getCause() instanceof FuncallException) {
+ throw new EvalException(getLocation(), e.getCause().getMessage());
+ } else if (e.getCause() != null) {
+ throw new EvalExceptionWithJavaCause(getLocation(), e.getCause());
+ } else {
+ // This is unlikely to happen
+ throw new EvalException(getLocation(), "Method invocation failed: " + e);
+ }
+ } catch (ExecutionException e) {
+ throw new EvalException(getLocation(), "Method invocation failed: " + e);
+ }
+ }
+
+ private String formatMethod(String methodName, List<Object> args) {
+ StringBuilder sb = new StringBuilder();
+ sb.append(methodName).append("(");
+ boolean first = true;
+ for (Object obj : args) {
+ if (!first) {
+ sb.append(", ");
+ }
+ sb.append(EvalUtils.getDatatypeName(obj));
+ first = false;
+ }
+ return sb.append(")").toString();
+ }
+
+ /**
+ * Add one argument to the keyword map, raising an exception when names conflict.
+ */
+ private void addKeywordArg(Map<String, Object> kwargs, String name, Object value)
+ throws EvalException {
+ if (kwargs.put(name, value) != null) {
+ throw new EvalException(getLocation(),
+ "duplicate keyword '" + name + "' in call to '" + func + "'");
+ }
+ }
+
+ /**
+ * Add multiple arguments to the keyword map (**kwargs).
+ */
+ private void addKeywordArgs(Map<String, Object> kwargs, Object items)
+ throws EvalException {
+ if (!(items instanceof Map<?, ?>)) {
+ throw new EvalException(getLocation(),
+ "Argument after ** must be a dictionary, not " + EvalUtils.getDatatypeName(items));
+ }
+ for (Map.Entry<?, ?> entry : ((Map<?, ?>) items).entrySet()) {
+ if (!(entry.getKey() instanceof String)) {
+ throw new EvalException(getLocation(),
+ "Keywords must be strings, not " + EvalUtils.getDatatypeName(entry.getKey()));
+ }
+ addKeywordArg(kwargs, (String) entry.getKey(), entry.getValue());
+ }
+ }
+
+ private void evalArguments(List<Object> posargs, Map<String, Object> kwargs,
+ Environment env, Function function)
+ throws EvalException, InterruptedException {
+ ArgConversion conversion = getArgConversion(function);
+ for (Argument arg : args) {
+ Object value = arg.getValue().eval(env);
+ if (conversion == ArgConversion.FROM_SKYLARK) {
+ value = SkylarkType.convertFromSkylark(value);
+ } else if (conversion == ArgConversion.TO_SKYLARK) {
+ // We try to auto convert the type if we can.
+ value = SkylarkType.convertToSkylark(value, getLocation());
+ // We call into Skylark so we need to be sure that the caller uses the appropriate types.
+ SkylarkType.checkTypeAllowedInSkylark(value, getLocation());
+ }
+ if (arg.isPositional()) {
+ posargs.add(value);
+ } else if (arg.isKwargs()) { // expand the kwargs
+ addKeywordArgs(kwargs, value);
+ } else {
+ addKeywordArg(kwargs, arg.getArgName(), value);
+ }
+ }
+ if (function instanceof UserDefinedFunction) {
+ // Adding the default values for a UserDefinedFunction if needed.
+ UserDefinedFunction func = (UserDefinedFunction) function;
+ if (args.size() < func.getArgs().size()) {
+ for (Map.Entry<String, Object> entry : func.getDefaultValues().entrySet()) {
+ String key = entry.getKey();
+ if (func.getArgIndex(key) >= numPositionalArgs && !kwargs.containsKey(key)) {
+ kwargs.put(key, entry.getValue());
+ }
+ }
+ }
+ }
+ }
+
+ static boolean isNamespace(Class<?> classObject) {
+ return classObject.isAnnotationPresent(SkylarkModule.class)
+ && classObject.getAnnotation(SkylarkModule.class).namespace();
+ }
+
+ @Override
+ Object eval(Environment env) throws EvalException, InterruptedException {
+ List<Object> posargs = new ArrayList<>();
+ Map<String, Object> kwargs = new LinkedHashMap<>();
+
+ if (obj != null) {
+ Object objValue = obj.eval(env);
+ // Strings, lists and dictionaries (maps) have functions that we want to use in MethodLibrary.
+ // For other classes, we can call the Java methods.
+ Function function =
+ env.getFunction(EvalUtils.getSkylarkType(objValue.getClass()), func.getName());
+ if (function != null) {
+ if (!isNamespace(objValue.getClass())) {
+ posargs.add(objValue);
+ }
+ evalArguments(posargs, kwargs, env, function);
+ return EvalUtils.checkNotNull(this, function.call(posargs, kwargs, this, env));
+ } else if (env.isSkylarkEnabled()) {
+
+ // When calling a Java method, the name is not in the Environment, so
+ // evaluating 'func' would fail. For arguments we don't need to consider the default
+ // arguments since the Java function doesn't have any.
+
+ evalArguments(posargs, kwargs, env, null);
+ if (!kwargs.isEmpty()) {
+ throw new EvalException(func.getLocation(),
+ "Keyword arguments are not allowed when calling a java method");
+ }
+ if (objValue instanceof Class<?>) {
+ // Static Java method call
+ return invokeJavaMethod(null, (Class<?>) objValue, func.getName(), posargs);
+ } else {
+ return invokeJavaMethod(objValue, objValue.getClass(), func.getName(), posargs);
+ }
+ } else {
+ throw new EvalException(getLocation(), String.format(
+ "function '%s' is not defined on '%s'", func.getName(),
+ EvalUtils.getDatatypeName(objValue)));
+ }
+ }
+
+ Object funcValue = func.eval(env);
+ if (!(funcValue instanceof Function)) {
+ throw new EvalException(getLocation(),
+ "'" + EvalUtils.getDatatypeName(funcValue)
+ + "' object is not callable");
+ }
+ Function function = (Function) funcValue;
+ evalArguments(posargs, kwargs, env, function);
+ return EvalUtils.checkNotNull(this, function.call(posargs, kwargs, this, env));
+ }
+
+ private ArgConversion getArgConversion(Function function) {
+ if (function == null) {
+ // It means we try to call a Java function.
+ return ArgConversion.FROM_SKYLARK;
+ }
+ // If we call a UserDefinedFunction we call into Skylark. If we call from Skylark
+ // the argument conversion is invariant, but if we call from the BUILD language
+ // we might need an auto conversion.
+ return function instanceof UserDefinedFunction
+ ? ArgConversion.TO_SKYLARK : ArgConversion.NO_CONVERSION;
+ }
+
+ @Override
+ public void accept(SyntaxTreeVisitor visitor) {
+ visitor.visit(this);
+ }
+
+ @Override
+ SkylarkType validate(ValidationEnvironment env) throws EvalException {
+ // TODO(bazel-team): implement semantical check.
+
+ if (obj != null) {
+ // TODO(bazel-team): validate function calls on objects too.
+ return env.getReturnType(obj.validate(env), func.getName(), getLocation());
+ } else {
+ // TODO(bazel-team): Imported functions are not validated properly.
+ if (!env.hasSymbolInEnvironment(func.getName())) {
+ throw new EvalException(getLocation(),
+ String.format("function '%s' does not exist", func.getName()));
+ }
+ return env.getReturnType(func.getName(), getLocation());
+ }
+ }
+}
