| // 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.annotations.VisibleForTesting; |
| import com.google.common.base.Joiner; |
| 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.List; |
| import java.util.Map; |
| import java.util.concurrent.ExecutionException; |
| |
| import javax.annotation.Nullable; |
| |
| /** |
| * 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(); |
| } |
| |
| @Nullable |
| 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); |
| } |
| } |
| |
| @Nullable private final Expression obj; |
| |
| private final Identifier func; |
| |
| private final List<Argument.Passed> 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(@Nullable Expression obj, Identifier func, |
| List<Argument.Passed> args) { |
| this.obj = obj; |
| this.func = func; |
| this.args = args; // we assume the parser validated it with Argument#validateFuncallArguments() |
| 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(Identifier func, List<Argument.Passed> args) { |
| this(null, func, args); |
| } |
| |
| /** |
| * Returns the number of positional arguments. |
| */ |
| private int countPositionalArguments() { |
| int num = 0; |
| for (Argument.Passed arg : args) { |
| if (arg.isPositional()) { |
| num++; |
| } |
| } |
| return num; |
| } |
| |
| /** |
| * Returns the function expression. |
| */ |
| public Identifier 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.Passed> getArguments() { |
| return Collections.unmodifiableList(args); |
| } |
| |
| /** |
| * Returns the number of arguments which are positional; the remainder are |
| * keyword arguments. |
| */ |
| public int getNumPositionalArguments() { |
| return numPositionalArgs; |
| } |
| |
| private String functionName() { |
| String name = func.getName(); |
| if (name.equals("$slice")) { |
| return "operator [:]"; |
| } else if (name.equals("$index")) { |
| return "operator []"; |
| } else { |
| return "function " + name; |
| } |
| } |
| |
| @Override |
| public String toString() { |
| if (func.getName().equals("$slice")) { |
| return obj + "[" + args.get(0) + ":" + args.get(1) + "]"; |
| } |
| if (func.getName().equals("$index")) { |
| return obj + "[" + args.get(0) + "]"; |
| } |
| StringBuilder sb = new StringBuilder(); |
| if (obj != null) { |
| sb.append(obj).append("."); |
| } |
| Printer.printList(sb.append(func), args, "(", ", ", ")", null); |
| return sb.toString(); |
| } |
| |
| /** |
| * 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, |
| Location loc) throws EvalException { |
| try { |
| return methodCache.get(objClass).get(methodName + "#" + argNum); |
| } catch (ExecutionException e) { |
| throw new EvalException(loc, "Method invocation failed: " + e); |
| } |
| } |
| |
| /** |
| * 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 { |
| try { |
| 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 Runtime.NONE; |
| } |
| if (result == null) { |
| if (methodDescriptor.getAnnotation().allowReturnNones()) { |
| return Runtime.NONE; |
| } else { |
| throw new EvalException(loc, |
| "Method invocation returned None, please contact Skylark developers: " + methodName |
| + Printer.listString(ImmutableList.copyOf(args), "(", ", ", ")", null)); |
| } |
| } |
| 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; |
| } 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(loc, "Method invocation failed: " + e); |
| } catch (InvocationTargetException e) { |
| if (e.getCause() instanceof FuncallException) { |
| throw new EvalException(loc, e.getCause().getMessage()); |
| } else if (e.getCause() != null) { |
| throw new EvalExceptionWithJavaCause(loc, e.getCause()); |
| } else { |
| // This is unlikely to happen |
| throw new EvalException(loc, "Method invocation failed: " + e); |
| } |
| } |
| } |
| |
| // 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. |
| private MethodDescriptor findJavaMethod( |
| Class<?> objClass, String methodName, List<Object> args) throws EvalException { |
| MethodDescriptor matchingMethod = null; |
| List<MethodDescriptor> methods = getMethods(objClass, methodName, args.size(), getLocation()); |
| 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( |
| getLocation(), |
| String.format( |
| "Type %s has multiple matches for %s", |
| EvalUtils.getDataTypeNameFromClass(objClass), |
| formatMethod(args))); |
| } |
| } |
| } |
| } |
| if (matchingMethod != null && !matchingMethod.getAnnotation().structField()) { |
| return matchingMethod; |
| } |
| throw new EvalException( |
| getLocation(), |
| String.format( |
| "Type %s has no %s", |
| EvalUtils.getDataTypeNameFromClass(objClass), |
| formatMethod(args))); |
| } |
| |
| private String formatMethod(List<Object> args) { |
| StringBuilder sb = new StringBuilder(); |
| sb.append(functionName()).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, registering a duplicate in case of conflict. |
| */ |
| private void addKeywordArg(Map<String, Object> kwargs, String name, |
| Object value, ImmutableList.Builder<String> duplicates) { |
| if (kwargs.put(name, value) != null) { |
| duplicates.add(name); |
| } |
| } |
| |
| /** |
| * Add multiple arguments to the keyword map (**kwargs), registering duplicates |
| */ |
| private void addKeywordArgs(Map<String, Object> kwargs, |
| Object items, ImmutableList.Builder<String> duplicates) 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(), duplicates); |
| } |
| } |
| |
| @SuppressWarnings("unchecked") |
| private void evalArguments(ImmutableList.Builder<Object> posargs, Map<String, Object> kwargs, |
| Environment env, BaseFunction function) |
| throws EvalException, InterruptedException { |
| ArgConversion conversion = getArgConversion(function); |
| ImmutableList.Builder<String> duplicates = new ImmutableList.Builder<>(); |
| // Iterate over the arguments. We assume all positional arguments come before any keyword |
| // or star arguments, because the argument list was already validated by |
| // Argument#validateFuncallArguments, as called by the Parser, |
| // which should be the only place that build FuncallExpression-s. |
| for (Argument.Passed 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()); |
| } // else NO_CONVERSION |
| if (arg.isPositional()) { |
| posargs.add(value); |
| } else if (arg.isStar()) { // expand the starArg |
| if (value instanceof Iterable) { |
| posargs.addAll((Iterable<Object>) value); |
| } |
| } else if (arg.isStarStar()) { // expand the kwargs |
| addKeywordArgs(kwargs, value, duplicates); |
| } else { |
| addKeywordArg(kwargs, arg.getName(), value, duplicates); |
| } |
| } |
| List<String> dups = duplicates.build(); |
| if (!dups.isEmpty()) { |
| throw new EvalException(getLocation(), |
| "duplicate keyword" + (dups.size() > 1 ? "s" : "") + " '" |
| + Joiner.on("', '").join(dups) |
| + "' in call to " + func); |
| } |
| } |
| |
| @VisibleForTesting |
| public static boolean isNamespace(Class<?> classObject) { |
| return classObject.isAnnotationPresent(SkylarkModule.class) |
| && classObject.getAnnotation(SkylarkModule.class).namespace(); |
| } |
| |
| @Override |
| Object eval(Environment env) throws EvalException, InterruptedException { |
| return (obj != null) ? invokeObjectMethod(env) : invokeGlobalFunction(env); |
| } |
| |
| /** |
| * Invokes obj.func() and returns the result. |
| */ |
| private Object invokeObjectMethod(Environment env) throws EvalException, InterruptedException { |
| Object objValue = obj.eval(env); |
| ImmutableList.Builder<Object> posargs = new ImmutableList.Builder<>(); |
| // We copy this into an ImmutableMap in the end, but we can't use an ImmutableMap.Builder, or |
| // we'd still have to have a HashMap on the side for the sake of properly handling duplicates. |
| Map<String, Object> kwargs = new HashMap<>(); |
| |
| // Strings, lists and dictionaries (maps) have functions that we want to use in |
| // MethodLibrary. |
| // For other classes, we can call the Java methods. |
| BaseFunction function = |
| Runtime.getFunction(EvalUtils.getSkylarkType(objValue.getClass()), func.getName()); |
| if (function != null) { |
| if (!isNamespace(objValue.getClass())) { |
| // Add self as an implicit parameter in front. |
| posargs.add(objValue); |
| } |
| evalArguments(posargs, kwargs, env, function); |
| return convertFromSkylark( |
| function.call(posargs.build(), ImmutableMap.<String, Object>copyOf(kwargs), this, env), |
| env); |
| } else if (objValue instanceof ClassObject) { |
| Object fieldValue = ((ClassObject) objValue).getValue(func.getName()); |
| if (fieldValue == null) { |
| throw new EvalException( |
| getLocation(), String.format("struct has no method '%s'", func.getName())); |
| } |
| if (!(fieldValue instanceof BaseFunction)) { |
| throw new EvalException( |
| getLocation(), String.format("struct field '%s' is not a function", func.getName())); |
| } |
| function = (BaseFunction) fieldValue; |
| evalArguments(posargs, kwargs, env, function); |
| return convertFromSkylark( |
| function.call(posargs.build(), ImmutableMap.<String, Object>copyOf(kwargs), this, env), |
| env); |
| } else if (env.isSkylark()) { |
| // Only allow native Java calls when using Skylark |
| // When calling a Java method, the name is not in the Environment, |
| // so evaluating 'func' would fail. |
| evalArguments(posargs, kwargs, env, null); |
| Class<?> objClass; |
| Object obj; |
| if (objValue instanceof Class<?>) { |
| // Static call |
| obj = null; |
| objClass = (Class<?>) objValue; |
| } else { |
| obj = objValue; |
| objClass = objValue.getClass(); |
| } |
| String name = func.getName(); |
| ImmutableList<Object> args = posargs.build(); |
| MethodDescriptor method = findJavaMethod(objClass, name, args); |
| if (!kwargs.isEmpty()) { |
| throw new EvalException( |
| func.getLocation(), |
| String.format( |
| "Keyword arguments are not allowed when calling a java method" |
| + "\nwhile calling method '%s' for type %s", |
| name, EvalUtils.getDataTypeNameFromClass(objClass))); |
| } |
| return callMethod(method, name, obj, args.toArray(), getLocation()); |
| } else { |
| throw new EvalException( |
| getLocation(), |
| String.format("%s is not defined on object of type '%s'", functionName(), |
| EvalUtils.getDataTypeName(objValue))); |
| } |
| } |
| |
| /** |
| * Invokes func() and returns the result. |
| */ |
| private Object invokeGlobalFunction(Environment env) throws EvalException, InterruptedException { |
| Object funcValue = func.eval(env); |
| ImmutableList.Builder<Object> posargs = new ImmutableList.Builder<>(); |
| // We copy this into an ImmutableMap in the end, but we can't use an ImmutableMap.Builder, or |
| // we'd still have to have a HashMap on the side for the sake of properly handling duplicates. |
| Map<String, Object> kwargs = new HashMap<>(); |
| if ((funcValue instanceof BaseFunction)) { |
| BaseFunction function = (BaseFunction) funcValue; |
| evalArguments(posargs, kwargs, env, function); |
| return convertFromSkylark( |
| function.call(posargs.build(), ImmutableMap.<String, Object>copyOf(kwargs), this, env), |
| env); |
| } else { |
| throw new EvalException( |
| getLocation(), "'" + EvalUtils.getDataTypeName(funcValue) + "' object is not callable"); |
| } |
| } |
| |
| protected Object convertFromSkylark(Object returnValue, Environment env) throws EvalException { |
| EvalUtils.checkNotNull(this, returnValue); |
| if (!env.isSkylark()) { |
| // The call happens in the BUILD language. Note that accessing "BUILD language" functions in |
| // Skylark should never happen. |
| return SkylarkType.convertFromSkylark(returnValue); |
| } |
| return returnValue; |
| } |
| |
| private ArgConversion getArgConversion(BaseFunction 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; |
| } |
| |
| /** |
| * Returns the value of the argument 'name' (or null if there is none). |
| * This function is used to associate debugging information to rules created by skylark "macros". |
| */ |
| @Nullable |
| public String getNameArg() { |
| for (Argument.Passed arg : args) { |
| if (arg != null) { |
| String name = arg.getName(); |
| if (name != null && name.equals("name")) { |
| Expression expr = arg.getValue(); |
| return (expr != null && expr instanceof StringLiteral) |
| ? ((StringLiteral) expr).getValue() : null; |
| } |
| } |
| } |
| return null; |
| } |
| |
| @Override |
| public void accept(SyntaxTreeVisitor visitor) { |
| visitor.visit(this); |
| } |
| |
| @Override |
| void validate(ValidationEnvironment env) throws EvalException { |
| for (Argument.Passed arg : args) { |
| arg.getValue().validate(env); |
| } |
| |
| if (obj != null) { |
| obj.validate(env); |
| } else if (!env.hasSymbolInEnvironment(func.getName())) { |
| throw new EvalException(getLocation(), |
| String.format("function '%s' does not exist", func.getName())); |
| } |
| } |
| } |