src/main/java/com/google/devtools/build/lib/syntax/Runtime.java - bazel - Git at Google

 // Copyright 2015 The Bazel Authors. 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.collect.ImmutableSet;
 import com.google.devtools.build.lib.concurrent.ThreadSafety.Immutable;
 import com.google.devtools.build.lib.skylarkinterface.SkylarkModule;
 import com.google.devtools.build.lib.skylarkinterface.SkylarkPrinter;
 import com.google.devtools.build.lib.skylarkinterface.SkylarkSignature;
 import com.google.devtools.build.lib.skylarkinterface.SkylarkValue;
 import java.lang.reflect.Field;
 import java.util.HashMap;
 import java.util.Map;
 import java.util.Set;

 /**
  * Global constants and support for global namespaces of runtime functions.
  */
 public final class Runtime {

   private Runtime() {}

   @SkylarkSignature(name = "True", returnType = Boolean.class,
       doc = "Literal for the boolean true.")
   private static final Boolean TRUE = true;

   @SkylarkSignature(name = "False", returnType = Boolean.class,
       doc = "Literal for the boolean false.")
   private static final Boolean FALSE = false;

   /** There should be only one instance of this type to allow "== None" tests. */
   @SkylarkModule(
     name = "NoneType",
     documented = false,
     doc = "Unit type, containing the unique value None."
   )
   @Immutable
   public static final class NoneType implements SkylarkValue {
     private NoneType() {}

     @Override
     public String toString() {
       return "None";
     }

     @Override
     public boolean isImmutable() {
       return true;
     }

     @Override
     public void repr(SkylarkPrinter printer) {
       printer.append("None");
     }
   }

   /** Marker for unbound variables in cases where neither Java null nor Skylark None is suitable. */
   @Immutable
   public static final class UnboundMarker implements SkylarkValue {
     private UnboundMarker() {}

     @Override
     public String toString() {
       return "<unbound>";
     }

     @Override
     public boolean isImmutable() {
       return true;
     }

     @Override
     public void repr(SkylarkPrinter printer) {
       printer.append("<unbound>");
     }
   }

   @SkylarkSignature(name = "<unbound>", returnType = UnboundMarker.class, documented = false,
       doc = "Marker for unbound values in cases where neither Skylark None nor Java null can do.")
   public static final UnboundMarker UNBOUND = new UnboundMarker();

   @SkylarkSignature(name = "None", returnType = NoneType.class,
       doc = "Literal for the None value.")
   public static final NoneType NONE = new NoneType();

   @SkylarkSignature(name = "PACKAGE_NAME", returnType = String.class,
       doc = "<b>Deprecated. Use <a href=\"native.html#package_name\">package_name()</a> "
           + "instead.</b> The name of the package being evaluated. "
           + "For example, in the BUILD file <code>some/package/BUILD</code>, its value "
           + "will be <code>some/package</code>. "
           + "If the BUILD file calls a function defined in a .bzl file, PACKAGE_NAME will "
           + "match the caller BUILD file package. "
           + "In .bzl files, do not access PACKAGE_NAME at the file-level (outside of functions), "
           + "either directly or by calling a function at the file-level that accesses "
           + "PACKAGE_NAME (PACKAGE_NAME is only defined during BUILD file evaluation)."
           + "Here is an example of a .bzl file:<br>"
           + "<pre class=language-python>"
           + "# a = PACKAGE_NAME  # not allowed outside functions\n"
           + "def extension():\n"
           + "  return PACKAGE_NAME</pre>"
           + "In this case, <code>extension()</code> can be called from a BUILD file (even "
           + "indirectly), but not in a file-level expression in the .bzl file. "
           + "When implementing a rule, use <a href=\"ctx.html#label\">ctx.label</a> to know where "
           + "the rule comes from. ")
   public static final String PKG_NAME = "PACKAGE_NAME";

   @SkylarkSignature(name = "REPOSITORY_NAME", returnType = String.class,
       doc = "<b>Deprecated. Use <a href=\"native.html#repository_name\">repository_name()</a> "
           + "instead.</b> The name of the repository the rule or build extension is called from. "
           + "For example, in packages that are called into existence by the WORKSPACE stanza "
           + "<code>local_repository(name='local', path=...)</code> it will be set to "
           + "<code>@local</code>. In packages in the main repository, it will be empty. "
           + "It can only be accessed in functions (transitively) called from BUILD files, i.e. "
           + "it follows the same restrictions as <a href=\"#PACKAGE_NAME\">PACKAGE_NAME</a>")
   public static final String REPOSITORY_NAME = "REPOSITORY_NAME";

   /**
    * Set up a given environment for supported class methods.
    */
   static Environment setupConstants(Environment env) {
     // In Python 2.x, True and False are global values and can be redefined by the user.
     // In Python 3.x, they are keywords. We implement them as values, for the sake of
     // simplicity. We define them as Boolean objects.
     return env.setup("False", FALSE).setup("True", TRUE).setup("None", NONE);
   }


   /** Global registry of functions associated to a class or namespace */
   private static final Map<Class<?>, Map<String, BaseFunction>> functions = new HashMap<>();

   /**
    * Registers a function with namespace to this global environment.
    */
   public static void registerFunction(Class<?> nameSpace, BaseFunction function) {
     Preconditions.checkNotNull(nameSpace);
     Preconditions.checkArgument(nameSpace.equals(getCanonicalRepresentation(nameSpace)));
     Preconditions.checkArgument(
         getCanonicalRepresentation(function.getObjectType()).equals(nameSpace));
     functions.computeIfAbsent(nameSpace, k -> new HashMap<String, BaseFunction>());
     functions.get(nameSpace).put(function.getName(), function);
   }

   /**
    * Returns the canonical representation of the given class, i.e. the super class for which any
    * functions were registered.
    *
    * <p>Currently, this is only necessary for mapping the different subclasses of {@link
    * java.util.Map} to the interface.
    */
   // TODO(bazel-team): make everything a SkylarkValue, and remove this function.
   public static Class<?> getCanonicalRepresentation(Class<?> clazz) {
     if (String.class.isAssignableFrom(clazz)) {
       return MethodLibrary.StringModule.class;
     }
     return EvalUtils.getSkylarkType(clazz);
   }


   static Map<String, BaseFunction> getNamespaceFunctions(Class<?> nameSpace) {
     return functions.get(getCanonicalRepresentation(nameSpace));
   }

   /**
    * Registers global fields with SkylarkSignature into the specified Environment.
    * @param env the Environment into which to register fields.
    * @param moduleClass the Class object containing globals.
    */
   public static void registerModuleGlobals(Environment env, Class<?> moduleClass) {
     try {
       if (moduleClass.isAnnotationPresent(SkylarkModule.class)) {
         env.setup(
             moduleClass.getAnnotation(SkylarkModule.class).name(),
             moduleClass.getConstructor().newInstance());
       }
       for (Field field : moduleClass.getDeclaredFields()) {
         if (field.isAnnotationPresent(SkylarkSignature.class)) {
           // Fields in Skylark modules are sometimes private.
           // Nevertheless they have to be annotated with SkylarkSignature.
           field.setAccessible(true);
           SkylarkSignature annotation = field.getAnnotation(SkylarkSignature.class);
           Object value = field.get(null);
           // Ignore function factories and non-global functions
           if (!(value instanceof BuiltinFunction.Factory
               || (value instanceof BaseFunction
                   && !annotation.objectType().equals(Object.class)))) {
             env.setup(annotation.name(), value);
           }
         }
       }
     } catch (ReflectiveOperationException e) {
       throw new AssertionError(e);
     }
   }

   /**
    * Returns the function of the namespace of the given name or null of it does not exists.
    */
   public static BaseFunction getFunction(Class<?> nameSpace, String name) {
     Map<String, BaseFunction> nameSpaceFunctions = getNamespaceFunctions(nameSpace);
     return nameSpaceFunctions != null ? nameSpaceFunctions.get(name) : null;
   }

   /**
    * Returns the function names registered with the namespace.
    */
   public static Set<String> getFunctionNames(Class<?> nameSpace) {
     Map<String, BaseFunction> nameSpaceFunctions = getNamespaceFunctions(nameSpace);
     return nameSpaceFunctions != null ? nameSpaceFunctions.keySet() : ImmutableSet.of();
   }

   static void setupMethodEnvironment(
       Environment env, Iterable<BaseFunction> functions) {
     for (BaseFunction function : functions) {
       env.setup(function.getName(), function);
     }
   }
 }
	// Copyright 2015 The Bazel Authors. 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.collect.ImmutableSet;
	import com.google.devtools.build.lib.concurrent.ThreadSafety.Immutable;
	import com.google.devtools.build.lib.skylarkinterface.SkylarkModule;
	import com.google.devtools.build.lib.skylarkinterface.SkylarkPrinter;
	import com.google.devtools.build.lib.skylarkinterface.SkylarkSignature;
	import com.google.devtools.build.lib.skylarkinterface.SkylarkValue;
	import java.lang.reflect.Field;
	import java.util.HashMap;
	import java.util.Map;
	import java.util.Set;

	/**
	* Global constants and support for global namespaces of runtime functions.
	*/
	public final class Runtime {

	private Runtime() {}

	@SkylarkSignature(name = "True", returnType = Boolean.class,
	doc = "Literal for the boolean true.")
	private static final Boolean TRUE = true;

	@SkylarkSignature(name = "False", returnType = Boolean.class,
	doc = "Literal for the boolean false.")
	private static final Boolean FALSE = false;

	/** There should be only one instance of this type to allow "== None" tests. */
	@SkylarkModule(
	name = "NoneType",
	documented = false,
	doc = "Unit type, containing the unique value None."
	)
	@Immutable
	public static final class NoneType implements SkylarkValue {
	private NoneType() {}

	@Override
	public String toString() {
	return "None";
	}

	@Override
	public boolean isImmutable() {
	return true;
	}

	@Override
	public void repr(SkylarkPrinter printer) {
	printer.append("None");
	}
	}

	/** Marker for unbound variables in cases where neither Java null nor Skylark None is suitable. */
	@Immutable
	public static final class UnboundMarker implements SkylarkValue {
	private UnboundMarker() {}

	@Override
	public String toString() {
	return "<unbound>";
	}

	@Override
	public boolean isImmutable() {
	return true;
	}

	@Override
	public void repr(SkylarkPrinter printer) {
	printer.append("<unbound>");
	}
	}

	@SkylarkSignature(name = "<unbound>", returnType = UnboundMarker.class, documented = false,
	doc = "Marker for unbound values in cases where neither Skylark None nor Java null can do.")
	public static final UnboundMarker UNBOUND = new UnboundMarker();

	@SkylarkSignature(name = "None", returnType = NoneType.class,
	doc = "Literal for the None value.")
	public static final NoneType NONE = new NoneType();

	@SkylarkSignature(name = "PACKAGE_NAME", returnType = String.class,
	doc = "<b>Deprecated. Use <a href=\"native.html#package_name\">package_name()</a> "
	+ "instead.</b> The name of the package being evaluated. "
	+ "For example, in the BUILD file <code>some/package/BUILD</code>, its value "
	+ "will be <code>some/package</code>. "
	+ "If the BUILD file calls a function defined in a .bzl file, PACKAGE_NAME will "
	+ "match the caller BUILD file package. "
	+ "In .bzl files, do not access PACKAGE_NAME at the file-level (outside of functions), "
	+ "either directly or by calling a function at the file-level that accesses "
	+ "PACKAGE_NAME (PACKAGE_NAME is only defined during BUILD file evaluation)."
	+ "Here is an example of a .bzl file:<br>"
	+ "<pre class=language-python>"
	+ "# a = PACKAGE_NAME # not allowed outside functions\n"
	+ "def extension():\n"
	+ " return PACKAGE_NAME</pre>"
	+ "In this case, <code>extension()</code> can be called from a BUILD file (even "
	+ "indirectly), but not in a file-level expression in the .bzl file. "
	+ "When implementing a rule, use <a href=\"ctx.html#label\">ctx.label</a> to know where "
	+ "the rule comes from. ")
	public static final String PKG_NAME = "PACKAGE_NAME";

	@SkylarkSignature(name = "REPOSITORY_NAME", returnType = String.class,
	doc = "<b>Deprecated. Use <a href=\"native.html#repository_name\">repository_name()</a> "
	+ "instead.</b> The name of the repository the rule or build extension is called from. "
	+ "For example, in packages that are called into existence by the WORKSPACE stanza "
	+ "<code>local_repository(name='local', path=...)</code> it will be set to "
	+ "<code>@local</code>. In packages in the main repository, it will be empty. "
	+ "It can only be accessed in functions (transitively) called from BUILD files, i.e. "
	+ "it follows the same restrictions as <a href=\"#PACKAGE_NAME\">PACKAGE_NAME</a>")
	public static final String REPOSITORY_NAME = "REPOSITORY_NAME";

	/**
	* Set up a given environment for supported class methods.
	*/
	static Environment setupConstants(Environment env) {
	// In Python 2.x, True and False are global values and can be redefined by the user.
	// In Python 3.x, they are keywords. We implement them as values, for the sake of
	// simplicity. We define them as Boolean objects.
	return env.setup("False", FALSE).setup("True", TRUE).setup("None", NONE);
	}


	/** Global registry of functions associated to a class or namespace */
	private static final Map<Class<?>, Map<String, BaseFunction>> functions = new HashMap<>();

	/**
	* Registers a function with namespace to this global environment.
	*/
	public static void registerFunction(Class<?> nameSpace, BaseFunction function) {
	Preconditions.checkNotNull(nameSpace);
	Preconditions.checkArgument(nameSpace.equals(getCanonicalRepresentation(nameSpace)));
	Preconditions.checkArgument(
	getCanonicalRepresentation(function.getObjectType()).equals(nameSpace));
	functions.computeIfAbsent(nameSpace, k -> new HashMap<String, BaseFunction>());
	functions.get(nameSpace).put(function.getName(), function);
	}

	/**
	* Returns the canonical representation of the given class, i.e. the super class for which any
	* functions were registered.
	*
	* <p>Currently, this is only necessary for mapping the different subclasses of {@link
	* java.util.Map} to the interface.
	*/
	// TODO(bazel-team): make everything a SkylarkValue, and remove this function.
	public static Class<?> getCanonicalRepresentation(Class<?> clazz) {
	if (String.class.isAssignableFrom(clazz)) {
	return MethodLibrary.StringModule.class;
	}
	return EvalUtils.getSkylarkType(clazz);
	}


	static Map<String, BaseFunction> getNamespaceFunctions(Class<?> nameSpace) {
	return functions.get(getCanonicalRepresentation(nameSpace));
	}

	/**
	* Registers global fields with SkylarkSignature into the specified Environment.
	* @param env the Environment into which to register fields.
	* @param moduleClass the Class object containing globals.
	*/
	public static void registerModuleGlobals(Environment env, Class<?> moduleClass) {
	try {
	if (moduleClass.isAnnotationPresent(SkylarkModule.class)) {
	env.setup(
	moduleClass.getAnnotation(SkylarkModule.class).name(),
	moduleClass.getConstructor().newInstance());
	}
	for (Field field : moduleClass.getDeclaredFields()) {
	if (field.isAnnotationPresent(SkylarkSignature.class)) {
	// Fields in Skylark modules are sometimes private.
	// Nevertheless they have to be annotated with SkylarkSignature.
	field.setAccessible(true);
	SkylarkSignature annotation = field.getAnnotation(SkylarkSignature.class);
	Object value = field.get(null);
	// Ignore function factories and non-global functions
	if (!(value instanceof BuiltinFunction.Factory
	\|\| (value instanceof BaseFunction
	&& !annotation.objectType().equals(Object.class)))) {
	env.setup(annotation.name(), value);
	}
	}
	}
	} catch (ReflectiveOperationException e) {
	throw new AssertionError(e);
	}
	}

	/**
	* Returns the function of the namespace of the given name or null of it does not exists.
	*/
	public static BaseFunction getFunction(Class<?> nameSpace, String name) {
	Map<String, BaseFunction> nameSpaceFunctions = getNamespaceFunctions(nameSpace);
	return nameSpaceFunctions != null ? nameSpaceFunctions.get(name) : null;
	}

	/**
	* Returns the function names registered with the namespace.
	*/
	public static Set<String> getFunctionNames(Class<?> nameSpace) {
	Map<String, BaseFunction> nameSpaceFunctions = getNamespaceFunctions(nameSpace);
	return nameSpaceFunctions != null ? nameSpaceFunctions.keySet() : ImmutableSet.of();
	}

	static void setupMethodEnvironment(
	Environment env, Iterable<BaseFunction> functions) {
	for (BaseFunction function : functions) {
	env.setup(function.getName(), function);
	}
	}
	}