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

 // Copyright 2016 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.devtools.build.lib.events.Location;
 import com.google.devtools.build.lib.skylarkinterface.SkylarkModule;
 import com.google.devtools.build.lib.skylarkinterface.SkylarkModuleCategory;
 import com.google.devtools.build.lib.skylarkinterface.SkylarkPrinter;
 import com.google.devtools.build.lib.syntax.SkylarkMutable.MutableMap;
 import java.util.LinkedHashMap;
 import java.util.Map;
 import javax.annotation.Nullable;

 /** Skylark Dict module. */
 @SkylarkModule(
   name = "dict",
   category = SkylarkModuleCategory.BUILTIN,
   doc =
       "A language built-in type representating a dictionary (associative mapping). "
           + "Dictionaries may be constructed with a special literal syntax:<br>"
           + "<pre class=\"language-python\">d = {\"a\": 2, \"b\": 5}</pre>"
           + "When using the literal syntax, it is an error to have duplicated keys. "
           + "Use square brackets to access elements:<br>"
           + "<pre class=\"language-python\">e = d[\"a\"]   # e == 2</pre>"
           + "Like lists, they can also be constructed using a comprehension syntax:<br>"
           + "<pre class=\"language-python\">d = {i: 2*i for i in range(20)}\n"
           + "e = d[8]       # e == 16</pre>"
           + "See also the <a href=\"globals.html#dict\">dict()</a> constructor function. "
           + "<p>Iterating over a dict is equivalent to iterating over its keys. The "
           + "<code>in</code> operator tests for membership in the keyset of the dict.<br>"
           + "<pre class=\"language-python\">\"a\" in {\"a\" : 2, \"b\" : 5} "
           + "# evaluates as True</pre>"
           + "The iteration order for a dict is deterministic but not specified."
 )
 public final class SkylarkDict<K, V> extends MutableMap<K, V>
     implements Map<K, V>, SkylarkIndexable {

   private final LinkedHashMap<K, V> contents = new LinkedHashMap<>();

   private final Mutability mutability;

   @Override
   public Mutability mutability() {
     return mutability;
   }

   private SkylarkDict(@Nullable Environment env) {
     mutability = env == null ? Mutability.IMMUTABLE : env.mutability();
   }

   /** @return a dict mutable in given environment only */
   public static <K, V> SkylarkDict<K, V> of(@Nullable Environment env) {
     return new SkylarkDict<>(env);
   }

   /** @return a dict mutable in given environment only, with given initial key and value */
   public static <K, V> SkylarkDict<K, V> of(@Nullable Environment env, K k, V v) {
     return SkylarkDict.<K, V>of(env).putUnsafe(k, v);
   }

   /** @return a dict mutable in given environment only, with two given initial key value pairs */
   public static <K, V> SkylarkDict<K, V> of(
       @Nullable Environment env, K k1, V v1, K k2, V v2) {
     return SkylarkDict.<K, V>of(env).putUnsafe(k1, v1).putUnsafe(k2, v2);
   }

   /** @return a dict mutable in given environment only, with contents copied from given map */
   public static <K, V> SkylarkDict<K, V> copyOf(
       @Nullable Environment env, Map<? extends K, ? extends V> m) {
     return SkylarkDict.<K, V>of(env).putAllUnsafe(m);
   }

   private SkylarkDict<K, V> putUnsafe(K k, V v) {
     contents.put(k, v);
     return this;
   }

   private <KK extends K, VV extends V> SkylarkDict putAllUnsafe(Map<KK, VV> m) {
     for (Map.Entry<KK, VV> e : m.entrySet()) {
       contents.put(e.getKey(), e.getValue());
     }
     return this;
   }

   /**
    * @return The underlying contents is a (usually) mutable data structure.
    * Read access is forwarded to these contents.
    * This object must not be modified outside an {@link Environment}
    * with a correct matching {@link Mutability},
    * which should be checked beforehand using {@link #checkMutable}.
    * it need not be an instance of {@link com.google.common.collect.ImmutableMap}.
    */
   @Override
   protected Map<K, V> getContentsUnsafe() {
     return contents;
   }

   /**
    * Put an entry into a SkylarkDict.
    * @param k the key
    * @param v the associated value
    * @param loc a {@link Location} in case of error
    * @param env an {@link Environment}, to check Mutability
    * @throws EvalException if the key is invalid
    */
   public void put(K k, V v, Location loc, Environment env) throws EvalException {
     checkMutable(loc, env);
     EvalUtils.checkValidDictKey(k);
     contents.put(k, v);
   }

   /**
    * Put all the entries from a given dict into the SkylarkDict.
    * @param m the map to copy
    * @param loc a {@link Location} in case of error
    * @param env an {@link Environment}, to check Mutability
    * @throws EvalException if some key is invalid
    */
   public <KK extends K, VV extends V> void putAll(Map<KK, VV> m, Location loc, Environment env)
       throws EvalException {
     checkMutable(loc, env);
     for (Map.Entry<KK, VV> e : m.entrySet()) {
       KK k = e.getKey();
       EvalUtils.checkValidDictKey(k);
       contents.put(k, e.getValue());
     }
   }

   /** @return the first key in the dict */
   K firstKey() {
     return contents.entrySet().iterator().next().getKey();
   }

   /**
    * Delete the entry associated to a key.
    * @param key the key to delete
    * @param loc a {@link Location} in case of error
    * @param env an {@link Environment}, to check Mutability
    * @return the value associated to the key, or {@code null} if not present
    * @throws EvalException if the dict is frozen.
    */
   V remove(Object key, Location loc, Environment env) throws EvalException {
     checkMutable(loc, env);
     return contents.remove(key);
   }

   /**
    * Clear the dict.
    * @param loc a {@link Location} in case of error
    * @param env an {@link Environment}, to check Mutability
    * @throws EvalException if the dict is frozen.
    */
   void clear(Location loc, Environment env) throws EvalException {
     checkMutable(loc, env);
     contents.clear();
   }

   // Other methods
   @Override
   public void repr(SkylarkPrinter printer) {
     printer.printList(entrySet(), "{", ", ", "}", null);
   }

   /**
    * Cast a SkylarkDict to a {@code Map<K, V>} after checking its current contents.
    * Treat None as meaning the empty ImmutableMap.
    * @param obj the Object to cast. null and None are treated as an empty list.
    * @param keyType the expected class of keys
    * @param valueType the expected class of values
    * @param description a description of the argument being converted, or null, for debugging
    */
   public static <K, V> SkylarkDict<K, V> castSkylarkDictOrNoneToDict(
       Object obj, Class<K> keyType, Class<V> valueType, @Nullable String description)
       throws EvalException {
     if (EvalUtils.isNullOrNone(obj)) {
       return empty();
     }
     if (obj instanceof SkylarkDict) {
       return ((SkylarkDict<?, ?>) obj).getContents(keyType, valueType, description);
     }
     throw new EvalException(
         null,
         String.format(
             "%s is not of expected type dict or NoneType",
             description == null ? Printer.repr(obj) : String.format("'%s'", description)));
   }

   /**
    * Cast a SkylarkDict to a {@code SkylarkDict<K, V>} after checking its current contents.
    * @param keyType the expected class of keys
    * @param valueType the expected class of values
    * @param description a description of the argument being converted, or null, for debugging
    */
   @SuppressWarnings("unchecked")
   public <KeyType, ValueType> SkylarkDict<KeyType, ValueType> getContents(
       Class<KeyType> keyType, Class<ValueType> valueType, @Nullable String description)
       throws EvalException {
     Object keyDescription = description == null
         ? null : Printer.formattable("'%s' key", description);
     Object valueDescription = description == null
         ? null : Printer.formattable("'%s' value", description);
     for (Map.Entry<?, ?> e : this.entrySet()) {
       SkylarkType.checkType(e.getKey(), keyType, keyDescription);
       SkylarkType.checkType(e.getValue(), valueType, valueDescription);
     }
     return (SkylarkDict<KeyType, ValueType>) this;
   }

   @Override
   public final Object getIndex(Object key, Location loc) throws EvalException {
     if (!this.containsKey(key)) {
       throw new EvalException(loc, Printer.format("key %r not found in dictionary", key));
     }
     return this.get(key);
   }

   @Override
   public final boolean containsKey(Object key, Location loc) throws EvalException {
     return this.containsKey(key);
   }

   public static <K, V> SkylarkDict<K, V> plus(
       SkylarkDict<? extends K, ? extends V> left,
       SkylarkDict<? extends K, ? extends V> right,
       @Nullable Environment env) {
     SkylarkDict<K, V> result = SkylarkDict.<K, V>of(env);
     result.putAllUnsafe(left);
     result.putAllUnsafe(right);
     return result;
   }

   private static final SkylarkDict<?, ?> EMPTY = of(null);

   public static <K, V> SkylarkDict<K, V> empty() {
     return (SkylarkDict<K, V>) EMPTY;
   }
 }
	// Copyright 2016 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.devtools.build.lib.events.Location;
	import com.google.devtools.build.lib.skylarkinterface.SkylarkModule;
	import com.google.devtools.build.lib.skylarkinterface.SkylarkModuleCategory;
	import com.google.devtools.build.lib.skylarkinterface.SkylarkPrinter;
	import com.google.devtools.build.lib.syntax.SkylarkMutable.MutableMap;
	import java.util.LinkedHashMap;
	import java.util.Map;
	import javax.annotation.Nullable;

	/** Skylark Dict module. */
	@SkylarkModule(
	name = "dict",
	category = SkylarkModuleCategory.BUILTIN,
	doc =
	"A language built-in type representating a dictionary (associative mapping). "
	+ "Dictionaries may be constructed with a special literal syntax:<br>"
	+ "<pre class=\"language-python\">d = {\"a\": 2, \"b\": 5}</pre>"
	+ "When using the literal syntax, it is an error to have duplicated keys. "
	+ "Use square brackets to access elements:<br>"
	+ "<pre class=\"language-python\">e = d[\"a\"] # e == 2</pre>"
	+ "Like lists, they can also be constructed using a comprehension syntax:<br>"
	+ "<pre class=\"language-python\">d = {i: 2*i for i in range(20)}\n"
	+ "e = d[8] # e == 16</pre>"
	+ "See also the <a href=\"globals.html#dict\">dict()</a> constructor function. "
	+ "<p>Iterating over a dict is equivalent to iterating over its keys. The "
	+ "<code>in</code> operator tests for membership in the keyset of the dict.<br>"
	+ "<pre class=\"language-python\">\"a\" in {\"a\" : 2, \"b\" : 5} "
	+ "# evaluates as True</pre>"
	+ "The iteration order for a dict is deterministic but not specified."
	)
	public final class SkylarkDict<K, V> extends MutableMap<K, V>
	implements Map<K, V>, SkylarkIndexable {

	private final LinkedHashMap<K, V> contents = new LinkedHashMap<>();

	private final Mutability mutability;

	@Override
	public Mutability mutability() {
	return mutability;
	}

	private SkylarkDict(@Nullable Environment env) {
	mutability = env == null ? Mutability.IMMUTABLE : env.mutability();
	}

	/** @return a dict mutable in given environment only */
	public static <K, V> SkylarkDict<K, V> of(@Nullable Environment env) {
	return new SkylarkDict<>(env);
	}

	/** @return a dict mutable in given environment only, with given initial key and value */
	public static <K, V> SkylarkDict<K, V> of(@Nullable Environment env, K k, V v) {
	return SkylarkDict.<K, V>of(env).putUnsafe(k, v);
	}

	/** @return a dict mutable in given environment only, with two given initial key value pairs */
	public static <K, V> SkylarkDict<K, V> of(
	@Nullable Environment env, K k1, V v1, K k2, V v2) {
	return SkylarkDict.<K, V>of(env).putUnsafe(k1, v1).putUnsafe(k2, v2);
	}

	/** @return a dict mutable in given environment only, with contents copied from given map */
	public static <K, V> SkylarkDict<K, V> copyOf(
	@Nullable Environment env, Map<? extends K, ? extends V> m) {
	return SkylarkDict.<K, V>of(env).putAllUnsafe(m);
	}

	private SkylarkDict<K, V> putUnsafe(K k, V v) {
	contents.put(k, v);
	return this;
	}

	private <KK extends K, VV extends V> SkylarkDict putAllUnsafe(Map<KK, VV> m) {
	for (Map.Entry<KK, VV> e : m.entrySet()) {
	contents.put(e.getKey(), e.getValue());
	}
	return this;
	}

	/**
	* @return The underlying contents is a (usually) mutable data structure.
	* Read access is forwarded to these contents.
	* This object must not be modified outside an {@link Environment}
	* with a correct matching {@link Mutability},
	* which should be checked beforehand using {@link #checkMutable}.
	* it need not be an instance of {@link com.google.common.collect.ImmutableMap}.
	*/
	@Override
	protected Map<K, V> getContentsUnsafe() {
	return contents;
	}

	/**
	* Put an entry into a SkylarkDict.
	* @param k the key
	* @param v the associated value
	* @param loc a {@link Location} in case of error
	* @param env an {@link Environment}, to check Mutability
	* @throws EvalException if the key is invalid
	*/
	public void put(K k, V v, Location loc, Environment env) throws EvalException {
	checkMutable(loc, env);
	EvalUtils.checkValidDictKey(k);
	contents.put(k, v);
	}

	/**
	* Put all the entries from a given dict into the SkylarkDict.
	* @param m the map to copy
	* @param loc a {@link Location} in case of error
	* @param env an {@link Environment}, to check Mutability
	* @throws EvalException if some key is invalid
	*/
	public <KK extends K, VV extends V> void putAll(Map<KK, VV> m, Location loc, Environment env)
	throws EvalException {
	checkMutable(loc, env);
	for (Map.Entry<KK, VV> e : m.entrySet()) {
	KK k = e.getKey();
	EvalUtils.checkValidDictKey(k);
	contents.put(k, e.getValue());
	}
	}

	/** @return the first key in the dict */
	K firstKey() {
	return contents.entrySet().iterator().next().getKey();
	}

	/**
	* Delete the entry associated to a key.
	* @param key the key to delete
	* @param loc a {@link Location} in case of error
	* @param env an {@link Environment}, to check Mutability
	* @return the value associated to the key, or {@code null} if not present
	* @throws EvalException if the dict is frozen.
	*/
	V remove(Object key, Location loc, Environment env) throws EvalException {
	checkMutable(loc, env);
	return contents.remove(key);
	}

	/**
	* Clear the dict.
	* @param loc a {@link Location} in case of error
	* @param env an {@link Environment}, to check Mutability
	* @throws EvalException if the dict is frozen.
	*/
	void clear(Location loc, Environment env) throws EvalException {
	checkMutable(loc, env);
	contents.clear();
	}

	// Other methods
	@Override
	public void repr(SkylarkPrinter printer) {
	printer.printList(entrySet(), "{", ", ", "}", null);
	}

	/**
	* Cast a SkylarkDict to a {@code Map<K, V>} after checking its current contents.
	* Treat None as meaning the empty ImmutableMap.
	* @param obj the Object to cast. null and None are treated as an empty list.
	* @param keyType the expected class of keys
	* @param valueType the expected class of values
	* @param description a description of the argument being converted, or null, for debugging
	*/
	public static <K, V> SkylarkDict<K, V> castSkylarkDictOrNoneToDict(
	Object obj, Class<K> keyType, Class<V> valueType, @Nullable String description)
	throws EvalException {
	if (EvalUtils.isNullOrNone(obj)) {
	return empty();
	}
	if (obj instanceof SkylarkDict) {
	return ((SkylarkDict<?, ?>) obj).getContents(keyType, valueType, description);
	}
	throw new EvalException(
	null,
	String.format(
	"%s is not of expected type dict or NoneType",
	description == null ? Printer.repr(obj) : String.format("'%s'", description)));
	}

	/**
	* Cast a SkylarkDict to a {@code SkylarkDict<K, V>} after checking its current contents.
	* @param keyType the expected class of keys
	* @param valueType the expected class of values
	* @param description a description of the argument being converted, or null, for debugging
	*/
	@SuppressWarnings("unchecked")
	public <KeyType, ValueType> SkylarkDict<KeyType, ValueType> getContents(
	Class<KeyType> keyType, Class<ValueType> valueType, @Nullable String description)
	throws EvalException {
	Object keyDescription = description == null
	? null : Printer.formattable("'%s' key", description);
	Object valueDescription = description == null
	? null : Printer.formattable("'%s' value", description);
	for (Map.Entry<?, ?> e : this.entrySet()) {
	SkylarkType.checkType(e.getKey(), keyType, keyDescription);
	SkylarkType.checkType(e.getValue(), valueType, valueDescription);
	}
	return (SkylarkDict<KeyType, ValueType>) this;
	}

	@Override
	public final Object getIndex(Object key, Location loc) throws EvalException {
	if (!this.containsKey(key)) {
	throw new EvalException(loc, Printer.format("key %r not found in dictionary", key));
	}
	return this.get(key);
	}

	@Override
	public final boolean containsKey(Object key, Location loc) throws EvalException {
	return this.containsKey(key);
	}

	public static <K, V> SkylarkDict<K, V> plus(
	SkylarkDict<? extends K, ? extends V> left,
	SkylarkDict<? extends K, ? extends V> right,
	@Nullable Environment env) {
	SkylarkDict<K, V> result = SkylarkDict.<K, V>of(env);
	result.putAllUnsafe(left);
	result.putAllUnsafe(right);
	return result;
	}

	private static final SkylarkDict<?, ?> EMPTY = of(null);

	public static <K, V> SkylarkDict<K, V> empty() {
	return (SkylarkDict<K, V>) EMPTY;
	}
	}