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package com.google.inject.internal;

import static com.google.inject.internal.Element.Type.MAPBINDER;
import static com.google.inject.internal.Errors.checkConfiguration;
import static com.google.inject.internal.Errors.checkNotNull;
import static com.google.inject.internal.RealMultibinder.setOf;
import static com.google.inject.util.Types.newParameterizedType;
import static com.google.inject.util.Types.newParameterizedTypeWithOwner;

import com.google.common.base.Objects;
import com.google.common.base.Preconditions;
import com.google.common.collect.HashMultimap;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.ImmutableMultimap;
import com.google.common.collect.ImmutableSet;
import com.google.common.collect.LinkedHashMultimap;
import com.google.common.collect.Lists;
import com.google.common.collect.Maps;
import com.google.common.collect.Multimap;
import com.google.common.collect.Sets;
import com.google.inject.Binder;
import com.google.inject.Binding;
import com.google.inject.Injector;
import com.google.inject.Key;
import com.google.inject.Module;
import com.google.inject.Provider;
import com.google.inject.TypeLiteral;
import com.google.inject.binder.LinkedBindingBuilder;
import com.google.inject.internal.InternalProviderInstanceBindingImpl.InitializationTiming;
import com.google.inject.multibindings.MapBinderBinding;
import com.google.inject.multibindings.Multibinder;
import com.google.inject.multibindings.MultibindingsTargetVisitor;
import com.google.inject.spi.BindingTargetVisitor;
import com.google.inject.spi.Dependency;
import com.google.inject.spi.Element;
import com.google.inject.spi.ProviderInstanceBinding;
import com.google.inject.spi.ProviderWithExtensionVisitor;
import com.google.inject.util.Types;
import java.lang.annotation.Annotation;
import java.lang.reflect.Type;
import java.util.Collection;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.Set;

/**
 * The actual mapbinder plays several roles:
 *
 * As a MapBinder, it acts as a factory for LinkedBindingBuilders for each of the map's values.
 * It delegates to a {@link Multibinder} of entries (keys to value providers).
 *
 * 
As a Module, it installs the binding to the map itself, as well as to a corresponding map
 * whose values are providers.
 *
 * 
As a module, this implements equals() and hashcode() in order to trick Guice into executing
 * its configure() method only once. That makes it so that multiple mapbinders can be created for
 * the same target map, but only one is bound. Since the list of bindings is retrieved from the
 * injector itself (and not the mapbinder), each mapbinder has access to all contributions from all
 * equivalent mapbinders.
 *
 * 
Rather than binding a single Map.Entry<K, V>, the map binder binds keys and values
 * independently. This allows the values to be properly scoped.
 */
public final class RealMapBinder implements Module {

  /**
   * Returns a new mapbinder that collects entries of {@code keyType}/{@code valueType} in a {@link
   * Map} that is itself bound with no binding annotation.
   */
  public static  RealMapBinder newMapRealBinder(
      Binder binder, TypeLiteral keyType, TypeLiteral valueType) {
    binder = binder.skipSources(RealMapBinder.class);
    return newRealMapBinder(
        binder,
        keyType,
        valueType,
        Key.get(mapOf(keyType, valueType)),
        RealMultibinder.newRealSetBinder(binder, Key.get(entryOfProviderOf(keyType, valueType))));
  }

  /**
   * Returns a new mapbinder that collects entries of {@code keyType}/{@code valueType} in a {@link
   * Map} that is itself bound with {@code annotation}.
   */
  public static  RealMapBinder newRealMapBinder(
      Binder binder, TypeLiteral keyType, TypeLiteral valueType, Annotation annotation) {
    binder = binder.skipSources(RealMapBinder.class);
    return newRealMapBinder(
        binder,
        keyType,
        valueType,
        Key.get(mapOf(keyType, valueType), annotation),
        RealMultibinder.newRealSetBinder(
            binder, Key.get(entryOfProviderOf(keyType, valueType), annotation)));
  }

  /**
   * Returns a new mapbinder that collects entries of {@code keyType}/{@code valueType} in a {@link
   * Map} that is itself bound with {@code annotationType}.
   */
  public static  RealMapBinder newRealMapBinder(
      Binder binder,
      TypeLiteral keyType,
      TypeLiteral valueType,
      Class annotationType) {
    binder = binder.skipSources(RealMapBinder.class);
    return newRealMapBinder(
        binder,
        keyType,
        valueType,
        Key.get(mapOf(keyType, valueType), annotationType),
        RealMultibinder.newRealSetBinder(
            binder, Key.get(entryOfProviderOf(keyType, valueType), annotationType)));
  }

  @SuppressWarnings("unchecked") // a map of  is safely a Map
  static  TypeLiteral> mapOf(TypeLiteral keyType, TypeLiteral valueType) {
    return (TypeLiteral>)
        TypeLiteral.get(Types.mapOf(keyType.getType(), valueType.getType()));
  }

  @SuppressWarnings("unchecked") // a provider map  is safely a Map>
  static  TypeLiteral>> mapOfProviderOf(
      TypeLiteral keyType, TypeLiteral valueType) {
    return (TypeLiteral>>)
        TypeLiteral.get(Types.mapOf(keyType.getType(), Types.providerOf(valueType.getType())));
  }

  // provider map  is safely a Map>>
  @SuppressWarnings("unchecked")
  static  TypeLiteral>> mapOfJavaxProviderOf(
      TypeLiteral keyType, TypeLiteral valueType) {
    return (TypeLiteral>>)
        TypeLiteral.get(
            Types.mapOf(
                keyType.getType(),
                newParameterizedType(javax.inject.Provider.class, valueType.getType())));
  }

  @SuppressWarnings("unchecked") // a provider map > is safely a Map>>
  static  TypeLiteral>>> mapOfSetOfProviderOf(
      TypeLiteral keyType, TypeLiteral valueType) {
    return (TypeLiteral>>>)
        TypeLiteral.get(
            Types.mapOf(keyType.getType(), Types.setOf(Types.providerOf(valueType.getType()))));
  }

  @SuppressWarnings("unchecked") // a provider map > is safely a Map>>
  static  TypeLiteral>>> mapOfSetOfJavaxProviderOf(
      TypeLiteral keyType, TypeLiteral valueType) {
    return (TypeLiteral>>>)
        TypeLiteral.get(
            Types.mapOf(
                keyType.getType(), Types.setOf(Types.javaxProviderOf(valueType.getType()))));
  }

  @SuppressWarnings("unchecked") // a provider map > is safely a Map>>
  static  TypeLiteral>>> mapOfCollectionOfProviderOf(
      TypeLiteral keyType, TypeLiteral valueType) {
    return (TypeLiteral>>>)
        TypeLiteral.get(
            Types.mapOf(
                keyType.getType(), Types.collectionOf(Types.providerOf(valueType.getType()))));
  }

  @SuppressWarnings("unchecked") // a provider map > is safely a Map>>
  static 
      TypeLiteral>>> mapOfCollectionOfJavaxProviderOf(
          TypeLiteral keyType, TypeLiteral valueType) {
    return (TypeLiteral>>>)
        TypeLiteral.get(
            Types.mapOf(
                keyType.getType(), Types.collectionOf(Types.javaxProviderOf(valueType.getType()))));
  }

  @SuppressWarnings("unchecked") // a provider entry  is safely a Map.Entry>
  static  TypeLiteral>> entryOfProviderOf(
      TypeLiteral keyType, TypeLiteral valueType) {
    return (TypeLiteral>>)
        TypeLiteral.get(
            newParameterizedTypeWithOwner(
                Map.class,
                Map.Entry.class,
                keyType.getType(),
                Types.providerOf(valueType.getType())));
  }

  @SuppressWarnings("unchecked") // a provider entry  is safely a Map.Entry>
  static  TypeLiteral>> entryOfJavaxProviderOf(
      TypeLiteral keyType, TypeLiteral valueType) {
    return (TypeLiteral>>)
        TypeLiteral.get(
            newParameterizedTypeWithOwner(
                Map.class,
                Map.Entry.class,
                keyType.getType(),
                Types.javaxProviderOf(valueType.getType())));
  }

  @SuppressWarnings("unchecked") // a provider entry  is safely a Map.Entry>
  static 
      TypeLiteral>>> setOfEntryOfJavaxProviderOf(
          TypeLiteral keyType, TypeLiteral valueType) {
    return (TypeLiteral>>>)
        TypeLiteral.get(Types.setOf(entryOfJavaxProviderOf(keyType, valueType).getType()));
  }

  /** Given a Key will return a Key> */
  @SuppressWarnings("unchecked")
  private static  Key> getKeyOfProvider(Key valueKey) {
    return (Key>)
        valueKey.ofType(Types.providerOf(valueKey.getTypeLiteral().getType()));
  }

  // Note: We use valueTypeAndAnnotation effectively as a Pair
  // since it's an easy way to group a type and an optional annotation type or instance.
  static  RealMapBinder newRealMapBinder(
      Binder binder, TypeLiteral keyType, Key valueTypeAndAnnotation) {
    binder = binder.skipSources(RealMapBinder.class);
    TypeLiteral valueType = valueTypeAndAnnotation.getTypeLiteral();
    return newRealMapBinder(
        binder,
        keyType,
        valueType,
        valueTypeAndAnnotation.ofType(mapOf(keyType, valueType)),
        RealMultibinder.newRealSetBinder(
            binder, valueTypeAndAnnotation.ofType(entryOfProviderOf(keyType, valueType))));
  }

  private static  RealMapBinder newRealMapBinder(
      Binder binder,
      TypeLiteral keyType,
      TypeLiteral valueType,
      Key> mapKey,
      RealMultibinder>> entrySetBinder) {
    RealMapBinder mapBinder =
        new RealMapBinder(binder, keyType, valueType, mapKey, entrySetBinder);
    binder.install(mapBinder);
    return mapBinder;
  }

  // Until the injector initializes us, we don't know what our dependencies are,
  // so initialize to the whole Injector.
  private static final ImmutableSet> MODULE_DEPENDENCIES =
      ImmutableSet.>of(Dependency.get(Key.get(Injector.class)));

  private final BindingSelection bindingSelection;
  private final Binder binder;

  private final RealMultibinder>> entrySetBinder;

  private RealMapBinder(
      Binder binder,
      TypeLiteral keyType,
      TypeLiteral valueType,
      Key> mapKey,
      RealMultibinder>> entrySetBinder) {
    this.bindingSelection = new BindingSelection<>(keyType, valueType, mapKey, entrySetBinder);
    this.binder = binder;
    this.entrySetBinder = entrySetBinder;
  }

  public void permitDuplicates() {
    checkConfiguration(!bindingSelection.isInitialized(), "MapBinder was already initialized");
    entrySetBinder.permitDuplicates();
    binder.install(new MultimapBinder(bindingSelection));
  }

  /** Adds a binding to the map for the given key. */
  Key getKeyForNewValue(K key) {
    checkNotNull(key, "key");
    checkConfiguration(!bindingSelection.isInitialized(), "MapBinder was already initialized");
    RealMultibinder>> entrySetBinder =
        bindingSelection.getEntrySetBinder();

    Key valueKey =
        Key.get(
            bindingSelection.getValueType(),
            new RealElement(
                entrySetBinder.getSetName(), MAPBINDER, bindingSelection.getKeyType().toString()));
    entrySetBinder.addBinding().toProvider(new ProviderMapEntry(key, valueKey));
    return valueKey;
  }

  /**
   * This creates two bindings. One for the {@code Map.Entry>} and another for {@code
   * V}.
   */
  public LinkedBindingBuilder addBinding(K key) {
    return binder.bind(getKeyForNewValue(key));
  }

  @Override
  public void configure(Binder binder) {
    checkConfiguration(!bindingSelection.isInitialized(), "MapBinder was already initialized");

    // Binds a Map>
    RealProviderMapProvider providerMapProvider =
        new RealProviderMapProvider<>(bindingSelection);
    binder.bind(bindingSelection.getProviderMapKey()).toProvider(providerMapProvider);

    // The map this exposes is internally an ImmutableMap, so it's OK to massage
    // the guice Provider to javax Provider in the value (since Guice provider
    // implements javax Provider).
    @SuppressWarnings({"unchecked", "rawtypes"})
    Provider>> javaxProviderMapProvider =
        (Provider) providerMapProvider;
    binder.bind(bindingSelection.getJavaxProviderMapKey()).toProvider(javaxProviderMapProvider);

    RealMapProvider mapProvider = new RealMapProvider<>(bindingSelection);
    // Bind Map to the provider w/ extension support.
    binder
        .bind(bindingSelection.getMapKey())
        .toProvider(new ExtensionRealMapProvider<>(mapProvider));
    // Bind Map to the provider w/o the extension support.
    binder.bind(bindingSelection.getMapOfKeyExtendsValueKey()).toProvider(mapProvider);

    // The Map.Entries are all ProviderMapEntry instances which do not allow setValue, so it is
    // safe to massage the return type like this
    @SuppressWarnings({"unchecked", "rawtypes"})
    Key>>> massagedEntrySetProviderKey =
        (Key) bindingSelection.getEntrySetBinder().getSetKey();
    binder.bind(bindingSelection.getEntrySetJavaxProviderKey()).to(massagedEntrySetProviderKey);
  }

  @Override
  public boolean equals(Object o) {
    return o instanceof RealMapBinder
        && ((RealMapBinder) o).bindingSelection.equals(bindingSelection);
  }

  @Override
  public int hashCode() {
    return bindingSelection.hashCode();
  }

  /**
   * The BindingSelection contains some of the core state and logic for the MapBinder.
   *
   * 
It lazily computes the value for keys for various permutations of Maps that are provided by
   * this module. It also builds up maps from {@code K} to {@code Binding}, which is used by all
   * of the internal factories to actually provide the desired maps.
   *
   * 
During initialization time there is only one BindingSelection. It is possible that multiple
   * different BindingSelections are constructed. Specifically, in the case of two different modules
   * each adding bindings to the same MapBinder. If that happens, we define the BindingSelection
   * held by the {@link RealMapProvider} to be the authoritative one. The logic for this exists in
   * {@link RealMultimapBinderProviderWithDependencies}. This is done to avoid confusion because the
   * BindingSelection contains mutable state.
   */
  private static final class BindingSelection {
    private enum InitializationState {
      UNINITIALIZED,
      INITIALIZED,
      HAS_ERRORS;
    }

    private final TypeLiteral keyType;
    private final TypeLiteral valueType;
    private final Key> mapKey;

    // Lazily computed
    private Key>> javaxProviderMapKey;
    private Key>> providerMapKey;
    private Key>> multimapKey;
    private Key>>> providerSetMultimapKey;
    private Key>>> javaxProviderSetMultimapKey;
    private Key>>> providerCollectionMultimapKey;
    private Key>>> javaxProviderCollectionMultimapKey;
    private Key>>> entrySetJavaxProviderKey;
    private Key> mapOfKeyExtendsValueKey;

    private final RealMultibinder>> entrySetBinder;

    private InitializationState initializationState;

    /**
     * These are built during initialization and used by all factories to actually provide the
     * relevant maps. These contain all of the necessary information about the map binder.
     */
    private ImmutableMap> mapBindings;

    private ImmutableMap>> multimapBindings;
    private ImmutableList>> entries;

    /**
     * Indicates if this Map permits duplicates. It is initialized during initialization by querying
     * the injector. This is done because multiple different modules can contribute to a MapBinder,
     * and any one could set permitDuplicates.
     */
    private boolean permitsDuplicates;

    private BindingSelection(
        TypeLiteral keyType,
        TypeLiteral valueType,
        Key> mapKey,
        RealMultibinder>> entrySetBinder) {
      this.keyType = keyType;
      this.valueType = valueType;
      this.mapKey = mapKey;
      this.entrySetBinder = entrySetBinder;
      this.initializationState = InitializationState.UNINITIALIZED;
    }

    /**
     * Will initialize internal data structures.
     *
     * @return {@code true} if initialization was successful, {@code false} if there were errors
     */
    private boolean tryInitialize(InjectorImpl injector, Errors errors) {
      // Every one of our providers will call this method, so only execute the logic once.
      if (initializationState != InitializationState.UNINITIALIZED) {
        return initializationState != InitializationState.HAS_ERRORS;
      }

      // Multiple different modules can all contribute to the same MapBinder, and if any
      // one of them permits duplicates, then the map binder as a whole will permit duplicates.
      // Since permitDuplicates() may not have been called on this instance, we need to go
      // to the injector to see if permitDuplicates was set.
      permitsDuplicates = entrySetBinder.permitsDuplicates(injector);

      // We now build the Map>> from the entrySetBinder.
      // The entrySetBinder contains all of the ProviderMapEntrys, and once
      // we have those, it's easy to iterate through them to organize them by K.
      Map>> bindingMultimapMutable =
          new LinkedHashMap>>();
      Map> bindingMapMutable = new LinkedHashMap<>();
      Multimap index = HashMultimap.create();
      Indexer indexer = new Indexer(injector);
      Multimap> duplicates = null;

      ImmutableList.Builder>> entriesBuilder = ImmutableList.builder();

      // We get all of the Bindings that were put into the entrySetBinder
      for (Binding>> binding :
          injector.findBindingsByType(entrySetBinder.getElementTypeLiteral())) {
        if (entrySetBinder.containsElement(binding)) {

          // Protected by findBindingByType() and the fact that all providers are added by us
          // in addBinding(). It would theoretically be possible for someone to directly
          // add their own binding to the entrySetBinder, but they shouldn't do that.
          @SuppressWarnings({"unchecked", "rawtypes"})
          ProviderInstanceBinding> entryBinding =
              (ProviderInstanceBinding) binding;

          // We added all these bindings initially, so we know they are ProviderMapEntrys
          @SuppressWarnings({"unchecked", "rawtypes"})
          ProviderMapEntry entry = (ProviderMapEntry) entryBinding.getUserSuppliedProvider();
          K key = entry.getKey();

          Key valueKey = entry.getValueKey();
          Binding valueBinding = injector.getExistingBinding(valueKey);

          // Use the indexer to de-dupe user bindings. This is needed because of the
          // uniqueId in RealElement. The uniqueId intentionally circumvents the regular
          // Guice deduplication, so we need to re-implement our own here, ignoring
          // uniqueId.
          if (index.put(key, valueBinding.acceptTargetVisitor(indexer))) {

            entriesBuilder.add(Maps.immutableEntry(key, valueBinding));

            Binding previous = bindingMapMutable.put(key, valueBinding);
            // Check if this is a duplicate binding
            if (previous != null && !permitsDuplicates) {
              if (duplicates == null) {
                // This is linked for both keys and values to maintain order
                duplicates = LinkedHashMultimap.create();
              }

              // We add both the previous and the current value to the duplicates map.
              // This is because if there are three duplicates, we will only execute this code
              // for the second and third, but we want all three values to display a helpful
              // error message. We rely on the multimap to dedupe repeated values.
              duplicates.put(key, previous);
              duplicates.put(key, valueBinding);
            }

            // Don't do extra work unless we need to
            if (permitsDuplicates) {
              // Add the binding, creating a set builder if it's the first time we've seen it
              bindingMultimapMutable
                  .computeIfAbsent(key, k -> ImmutableSet.builder())
                  .add(valueBinding);
            }
          }
        }
      }

      // It is safe to check if duplicates is non-null because if duplicates are allowed,
      // we don't build up this data structure
      if (duplicates != null) {
        initializationState = InitializationState.HAS_ERRORS;
        reportDuplicateKeysError(mapKey, duplicates, errors);

        return false;
      }

      // Build all of the ImmutableSet.Builders,
      // transforming from Map>> to
      // ImmutableMap>>
      ImmutableMap.Builder>> bindingsMultimapBuilder = ImmutableMap.builder();
      for (Map.Entry>> entry :
          bindingMultimapMutable.entrySet()) {
        bindingsMultimapBuilder.put(entry.getKey(), entry.getValue().build());
      }
      mapBindings = ImmutableMap.copyOf(bindingMapMutable);
      multimapBindings = bindingsMultimapBuilder.build();

      entries = entriesBuilder.build();

      initializationState = InitializationState.INITIALIZED;

      return true;
    }

    private static  void reportDuplicateKeysError(
        Key> mapKey, Multimap> duplicates, Errors errors) {
      errors.duplicateMapKey(mapKey, duplicates);
      return;
    }

    private boolean containsElement(Element element) {
      if (entrySetBinder.containsElement(element)) {
        return true;
      }

      Key key;
      if (element instanceof Binding) {
        key = ((Binding) element).getKey();
      } else {
        return false; // cannot match;
      }

      return key.equals(getMapKey())
          || key.equals(getProviderMapKey())
          || key.equals(getJavaxProviderMapKey())
          || key.equals(getMultimapKey())
          || key.equals(getProviderSetMultimapKey())
          || key.equals(getJavaxProviderSetMultimapKey())
          || key.equals(getProviderCollectionMultimapKey())
          || key.equals(getJavaxProviderCollectionMultimapKey())
          || key.equals(entrySetBinder.getSetKey())
          || key.equals(getEntrySetJavaxProviderKey())
          || key.equals(getMapOfKeyExtendsValueKey())
          || matchesValueKey(key);
    }

    /** Returns true if the key indicates this is a value in the map. */
    private boolean matchesValueKey(Key key) {
      return key.getAnnotation() instanceof RealElement
          && ((RealElement) key.getAnnotation()).setName().equals(entrySetBinder.getSetName())
          && ((RealElement) key.getAnnotation()).type() == MAPBINDER
          && ((RealElement) key.getAnnotation()).keyType().equals(keyType.toString())
          && key.getTypeLiteral().equals(valueType);
    }

    private Key>> getProviderMapKey() {
      Key>> local = providerMapKey;
      if (local == null) {
        local = providerMapKey = mapKey.ofType(mapOfProviderOf(keyType, valueType));
      }
      return local;
    }

    private Key>> getJavaxProviderMapKey() {
      Key>> local = javaxProviderMapKey;
      if (local == null) {
        local = javaxProviderMapKey = mapKey.ofType(mapOfJavaxProviderOf(keyType, valueType));
      }
      return local;
    }

    private Key>> getMultimapKey() {
      Key>> local = multimapKey;
      if (local == null) {
        local = multimapKey = mapKey.ofType(mapOf(keyType, setOf(valueType)));
      }
      return local;
    }

    private Key>>> getProviderSetMultimapKey() {
      Key>>> local = providerSetMultimapKey;
      if (local == null) {
        local = providerSetMultimapKey = mapKey.ofType(mapOfSetOfProviderOf(keyType, valueType));
      }
      return local;
    }

    private Key>>> getJavaxProviderSetMultimapKey() {
      Key>>> local = javaxProviderSetMultimapKey;
      if (local == null) {
        local =
            javaxProviderSetMultimapKey =
                mapKey.ofType(mapOfSetOfJavaxProviderOf(keyType, valueType));
      }
      return local;
    }

    private Key>>> getProviderCollectionMultimapKey() {
      Key>>> local = providerCollectionMultimapKey;
      if (local == null) {
        local =
            providerCollectionMultimapKey =
                mapKey.ofType(mapOfCollectionOfProviderOf(keyType, valueType));
      }
      return local;
    }

    private Key>>>
        getJavaxProviderCollectionMultimapKey() {
      Key>>> local = javaxProviderCollectionMultimapKey;
      if (local == null) {
        local =
            javaxProviderCollectionMultimapKey =
                mapKey.ofType(mapOfCollectionOfJavaxProviderOf(keyType, valueType));
      }
      return local;
    }

    private Key>>> getEntrySetJavaxProviderKey() {
      Key>>> local = entrySetJavaxProviderKey;
      if (local == null) {
        local =
            entrySetJavaxProviderKey =
                mapKey.ofType(setOfEntryOfJavaxProviderOf(keyType, valueType));
      }
      return local;
    }

    @SuppressWarnings("unchecked")
    private Key> getMapOfKeyExtendsValueKey() {
      Key> local = mapOfKeyExtendsValueKey;
      if (local == null) {
        Type extendsValue = Types.subtypeOf(valueType.getType());
        Type mapOfKeyAndExtendsValue = Types.mapOf(keyType.getType(), extendsValue);
        local =
            mapOfKeyExtendsValueKey =
                (Key>) mapKey.ofType(mapOfKeyAndExtendsValue);
      }
      return local;
    }

    private ImmutableMap> getMapBindings() {
      checkConfiguration(isInitialized(), "MapBinder has not yet been initialized");
      return mapBindings;
    }

    private ImmutableMap>> getMultimapBindings() {
      checkConfiguration(isInitialized(), "MapBinder has not yet been initialized");
      return multimapBindings;
    }

    private ImmutableList>> getEntries() {
      checkConfiguration(isInitialized(), "MapBinder has not yet been initialized");
      return entries;
    }

    private boolean isInitialized() {
      return initializationState == InitializationState.INITIALIZED;
    }

    private TypeLiteral getKeyType() {
      return keyType;
    }

    private TypeLiteral getValueType() {
      return valueType;
    }

    private Key> getMapKey() {
      return mapKey;
    }

    private RealMultibinder>> getEntrySetBinder() {
      return entrySetBinder;
    }

    private boolean permitsDuplicates() {
      if (isInitialized()) {
        return permitsDuplicates;
      } else {
        throw new UnsupportedOperationException(
            "permitsDuplicates() not supported for module bindings");
      }
    }

    @Override
    public boolean equals(Object o) {
      return o instanceof BindingSelection && ((BindingSelection) o).mapKey.equals(mapKey);
    }

    @Override
    public int hashCode() {
      return mapKey.hashCode();
    }
  }

  private static final class RealProviderMapProvider
      extends RealMapBinderProviderWithDependencies>> {
    private Map> mapOfProviders;
    private Set> dependencies = RealMapBinder.MODULE_DEPENDENCIES;

    private RealProviderMapProvider(BindingSelection bindingSelection) {
      super(bindingSelection);
    }

    @Override
    public Set> getDependencies() {
      return dependencies;
    }

    @Override
    protected void doInitialize(InjectorImpl injector, Errors errors) {
      ImmutableMap.Builder> mapOfProvidersBuilder = ImmutableMap.builder();
      ImmutableSet.Builder> dependenciesBuilder = ImmutableSet.builder();
      for (Map.Entry> entry : bindingSelection.getMapBindings().entrySet()) {
        mapOfProvidersBuilder.put(entry.getKey(), entry.getValue().getProvider());
        dependenciesBuilder.add(Dependency.get(getKeyOfProvider(entry.getValue().getKey())));
      }

      mapOfProviders = mapOfProvidersBuilder.build();
      dependencies = dependenciesBuilder.build();
    }

    @Override
    protected Map> doProvision(InternalContext context, Dependency dependency) {
      return mapOfProviders;
    }
  }

  private static final class RealMapProvider
      extends RealMapBinderProviderWithDependencies> {
    Set> dependencies = RealMapBinder.MODULE_DEPENDENCIES;

    /**
     * An array of all the injectors.
     *
     * 
This is parallel to array of keys below
     */
    SingleParameterInjector[] injectors;

    K[] keys;

    RealMapProvider(BindingSelection bindingSelection) {
      super(bindingSelection);
    }

    BindingSelection getBindingSelection() {
      return bindingSelection;
    }

    @Override
    protected void doInitialize(InjectorImpl injector, Errors errors) throws ErrorsException {
      @SuppressWarnings("unchecked")
      K[] keysArray = (K[]) new Object[bindingSelection.getMapBindings().size()];
      keys = keysArray;
      ImmutableSet.Builder> dependenciesBuilder = ImmutableSet.builder();
      int i = 0;
      for (Map.Entry> entry : bindingSelection.getMapBindings().entrySet()) {
        dependenciesBuilder.add(Dependency.get(entry.getValue().getKey()));
        keys[i] = entry.getKey();
        i++;
      }

      ImmutableSet> localDependencies = dependenciesBuilder.build();
      dependencies = localDependencies;

      List> dependenciesList = localDependencies.asList();

      // We know the type because we built up our own sets of dependencies, it's just
      // that the interface uses a "?" generic
      @SuppressWarnings("unchecked")
      SingleParameterInjector[] typedInjectors =
          (SingleParameterInjector[]) injector.getParametersInjectors(dependenciesList, errors);
      injectors = typedInjectors;
    }

    @Override
    protected Map doProvision(InternalContext context, Dependency dependency)
        throws InternalProvisionException {
      SingleParameterInjector[] localInjectors = injectors;
      if (localInjectors == null) {
        // if injectors == null, then we have no bindings so return the empty map.
        return ImmutableMap.of();
      }

      ImmutableMap.Builder resultBuilder = ImmutableMap.builder();
      K[] localKeys = keys;
      for (int i = 0; i < localInjectors.length; i++) {
        SingleParameterInjector injector = localInjectors[i];
        K key = localKeys[i];

        V value = injector.inject(context);

        if (value == null) {
          throw createNullValueException(key, bindingSelection.getMapBindings().get(key));
        }

        resultBuilder.put(key, value);
      }

      return resultBuilder.build();
    }

    @Override
    public Set> getDependencies() {
      return dependencies;
    }
  }

  /**
   * Implementation of a provider instance for the map that also exposes details about the MapBinder
   * using the extension SPI, delegating to another provider instance for non-extension (e.g, the
   * actual provider instance info) data.
   */
  private static final class ExtensionRealMapProvider
      extends RealMapBinderProviderWithDependencies>
      implements ProviderWithExtensionVisitor>, MapBinderBinding> {
    final RealMapProvider delegate;

    ExtensionRealMapProvider(RealMapProvider delegate) {
      super(delegate.bindingSelection);
      this.delegate = delegate;
    }

    BindingSelection getBindingSelection() {
      return bindingSelection;
    }

    @Override
    protected void doInitialize(InjectorImpl injector, Errors errors) throws ErrorsException {
      delegate.doInitialize(injector, errors);
    }

    @Override
    protected Map doProvision(InternalContext context, Dependency dependency)
        throws InternalProvisionException {
      return delegate.doProvision(context, dependency);
    }

    @Override
    public Set> getDependencies() {
      return delegate.getDependencies();
    }

    @Override
    @SuppressWarnings("unchecked")
    public  W acceptExtensionVisitor(
        BindingTargetVisitor visitor, ProviderInstanceBinding binding) {
      if (visitor instanceof MultibindingsTargetVisitor) {
        return ((MultibindingsTargetVisitor, W>) visitor).visit(this);
      } else {
        return visitor.visit(binding);
      }
    }

    @Override
    public Key> getMapKey() {
      return bindingSelection.getMapKey();
    }

    @Override
    public Set> getAlternateMapKeys() {
      return ImmutableSet.of(
          (Key) bindingSelection.getJavaxProviderMapKey(),
          (Key) bindingSelection.getProviderMapKey(),
          (Key) bindingSelection.getProviderSetMultimapKey(),
          (Key) bindingSelection.getJavaxProviderSetMultimapKey(),
          (Key) bindingSelection.getProviderCollectionMultimapKey(),
          (Key) bindingSelection.getJavaxProviderCollectionMultimapKey(),
          (Key) bindingSelection.getMultimapKey(),
          (Key) bindingSelection.getMapOfKeyExtendsValueKey());
    }

    @Override
    public TypeLiteral getKeyTypeLiteral() {
      return bindingSelection.getKeyType();
    }

    @Override
    public TypeLiteral getValueTypeLiteral() {
      return bindingSelection.getValueType();
    }

    @Override
    @SuppressWarnings("unchecked")
    public List>> getEntries() {
      if (bindingSelection.isInitialized()) {
        return (List>>) (List) bindingSelection.getEntries();
      } else {
        throw new UnsupportedOperationException("getEntries() not supported for module bindings");
      }
    }

    @Override
    public List>> getEntries(Iterable elements) {
      // Iterate over the elements, building up the below maps
      // This is a preprocessing step allowing us to only iterate over elements
      // once and have O(n) runtime
      ImmutableMultimap.Builder> keyToValueKeyBuilder = ImmutableMultimap.builder();
      ImmutableMap.Builder, Binding> valueKeyToBindingBuilder = ImmutableMap.builder();
      ImmutableMap.Builder, K> valueKeyToKeyBuilder = ImmutableMap.builder();
      ImmutableMap.Builder, Binding>>>
          valueKeyToEntryBindingBuilder = ImmutableMap.builder();
      for (Element element : elements) {
        if (element instanceof Binding) {
          Binding binding = (Binding) element;
          if (bindingSelection.matchesValueKey(binding.getKey())
              && binding.getKey().getTypeLiteral().equals(bindingSelection.valueType)) {
            // Safe because of the check on the type literal above
            @SuppressWarnings("unchecked")
            Binding typedBinding = (Binding) binding;
            Key typedKey = typedBinding.getKey();
            valueKeyToBindingBuilder.put(typedKey, typedBinding);
          }
        }

        if (element instanceof ProviderInstanceBinding
            && bindingSelection.getEntrySetBinder().containsElement(element)) {
          // Safe because of the instanceof check, and containsElement() check
          @SuppressWarnings({"unchecked", "rawtypes"})
          ProviderInstanceBinding>> entryBinding =
              (ProviderInstanceBinding) element;

          // Safe because of the check for containsElement() above
          @SuppressWarnings("unchecked")
          Provider>> typedProvider =
              (Provider>>) entryBinding.getUserSuppliedProvider();
          Provider>> userSuppliedProvider = typedProvider;

          if (userSuppliedProvider instanceof ProviderMapEntry) {
            // Safe because of the instanceof check
            @SuppressWarnings("unchecked")
            ProviderMapEntry typedUserSuppliedProvider =
                (ProviderMapEntry) userSuppliedProvider;
            ProviderMapEntry entry = typedUserSuppliedProvider;

            keyToValueKeyBuilder.put(entry.getKey(), entry.getValueKey());
            valueKeyToEntryBindingBuilder.put(entry.getValueKey(), entryBinding);
            valueKeyToKeyBuilder.put(entry.getValueKey(), entry.getKey());
          }
        }
      }

      ImmutableMultimap> keyToValueKey = keyToValueKeyBuilder.build();
      ImmutableMap, K> valueKeyToKey = valueKeyToKeyBuilder.build();
      ImmutableMap, Binding> valueKeyToBinding = valueKeyToBindingBuilder.build();
      ImmutableMap, Binding>>> valueKeyToEntryBinding =
          valueKeyToEntryBindingBuilder.build();

      // Check that there is a 1:1 mapping from keys from the ProviderMapEntrys to the
      // keys from the Bindings.
      Set> keysFromProviderMapEntrys = Sets.newHashSet(keyToValueKey.values());
      Set> keysFromBindings = valueKeyToBinding.keySet();

      if (!keysFromProviderMapEntrys.equals(keysFromBindings)) {
        Set> keysOnlyFromProviderMapEntrys =
            Sets.difference(keysFromProviderMapEntrys, keysFromBindings);
        Set> keysOnlyFromBindings =
            Sets.difference(keysFromBindings, keysFromProviderMapEntrys);

        StringBuilder sb = new StringBuilder("Expected a 1:1 mapping from map keys to values.");

        if (!keysOnlyFromBindings.isEmpty()) {
          sb.append(
              Errors.format("%nFound these Bindings that were missing an associated entry:%n"));
          for (Key key : keysOnlyFromBindings) {
            sb.append(
                Errors.format("  %s bound at: %s%n", key, valueKeyToBinding.get(key).getSource()));
          }
        }

        if (!keysOnlyFromProviderMapEntrys.isEmpty()) {
          sb.append(Errors.format("%nFound these map keys without a corresponding value:%n"));
          for (Key key : keysOnlyFromProviderMapEntrys) {
            sb.append(
                Errors.format(
                    "  '%s' bound at: %s%n",
                    valueKeyToKey.get(key), valueKeyToEntryBinding.get(key).getSource()));
          }
        }

        throw new IllegalArgumentException(sb.toString());
      }

      // Now that we have the two maps, generate the result map
      ImmutableList.Builder>> resultBuilder = ImmutableList.builder();
      for (Map.Entry> entry : keyToValueKey.entries()) {
        Binding binding = valueKeyToBinding.get(entry.getValue());
        // No null check for binding needed because of the above check to make sure all the
        // values in keyToValueKey are present as keys in valueKeyToBinding

        @SuppressWarnings({"unchecked", "rawtypes"})
        Map.Entry> newEntry =
            (Map.Entry) Maps.immutableEntry(entry.getKey(), binding);
        resultBuilder.add(newEntry);
      }
      return resultBuilder.build();
    }

    @Override
    public boolean permitsDuplicates() {
      if (bindingSelection.isInitialized()) {
        return bindingSelection.permitsDuplicates();
      } else {
        throw new UnsupportedOperationException(
            "permitsDuplicates() not supported for module bindings");
      }
    }

    @Override
    public boolean containsElement(Element element) {
      return bindingSelection.containsElement(element);
    }
  }

  /**
   * Binds {@code Map>} and {{@code Map>>}.
   *
   * 
This will only exist if permitDuplicates() is called.
   */
  private static final class MultimapBinder implements Module {
    private final BindingSelection bindingSelection;

    private MultimapBinder(BindingSelection bindingSelection) {
      this.bindingSelection = bindingSelection;
    }

    @Override
    public void configure(Binder binder) {
      // Binds a Map>>
      Provider>>> multimapProvider =
          new RealProviderMultimapProvider(bindingSelection.getMapKey());
      binder.bind(bindingSelection.getProviderSetMultimapKey()).toProvider(multimapProvider);

      // Provide links from a few different public keys to the providerMultimapKey.
      // The collection this exposes is internally an ImmutableMap, so it's OK to massage
      // the guice Provider to javax Provider in the value (since the guice Provider implements
      // javax Provider).
      @SuppressWarnings({"unchecked", "rawtypes"})
      Provider>>> javaxProvider = (Provider) multimapProvider;
      binder.bind(bindingSelection.getJavaxProviderSetMultimapKey()).toProvider(javaxProvider);

      @SuppressWarnings({"unchecked", "rawtypes"})
      Provider>>> collectionProvider = (Provider) multimapProvider;
      binder
          .bind(bindingSelection.getProviderCollectionMultimapKey())
          .toProvider(collectionProvider);

      @SuppressWarnings({"unchecked", "rawtypes"})
      Provider>>> collectionJavaxProvider =
          (Provider) multimapProvider;
      binder
          .bind(bindingSelection.getJavaxProviderCollectionMultimapKey())
          .toProvider(collectionJavaxProvider);

      // Binds a Map>
      @SuppressWarnings({"unchecked", "rawtypes"})
      Provider>> realMultimapProvider =
          new RealMultimapProvider(bindingSelection.getMapKey());
      binder.bind(bindingSelection.getMultimapKey()).toProvider(realMultimapProvider);
    }

    @Override
    public int hashCode() {
      return bindingSelection.hashCode();
    }

    @Override
    public boolean equals(Object o) {
      return o instanceof MultimapBinder
          && ((MultimapBinder) o).bindingSelection.equals(bindingSelection);
    }

    private static final class RealProviderMultimapProvider
        extends RealMultimapBinderProviderWithDependencies>>> {
      private Map>> multimapOfProviders;
      private Set> dependencies = RealMapBinder.MODULE_DEPENDENCIES;

      private RealProviderMultimapProvider(Key> mapKey) {
        super(mapKey);
      }

      @Override
      public Set> getDependencies() {
        return dependencies;
      }

      @Override
      protected void doInitialize(InjectorImpl injector, Errors errors) {
        ImmutableMap.Builder>> multimapOfProvidersBuilder =
            ImmutableMap.builder();
        ImmutableSet.Builder> dependenciesBuilder = ImmutableSet.builder();
        for (Map.Entry>> entry :
            bindingSelection.getMultimapBindings().entrySet()) {
          ImmutableSet.Builder> providersBuilder = ImmutableSet.builder();
          for (Binding binding : entry.getValue()) {
            providersBuilder.add(binding.getProvider());
            dependenciesBuilder.add(Dependency.get(getKeyOfProvider(binding.getKey())));
          }

          multimapOfProvidersBuilder.put(entry.getKey(), providersBuilder.build());
        }
        multimapOfProviders = multimapOfProvidersBuilder.build();
        dependencies = dependenciesBuilder.build();
      }

      @Override
      protected Map>> doProvision(
          InternalContext context, Dependency dependency) {
        return multimapOfProviders;
      }
    }

    private static final class RealMultimapProvider
        extends RealMultimapBinderProviderWithDependencies>> {

      /**
       * A simple class to hold a key and the associated bindings as an array.
       *
       * 
Arrays are used for performance.
       */
      private static final class PerKeyData {
        private final K key;
        private final Binding[] bindings;
        private final SingleParameterInjector[] injectors;

        private PerKeyData(K key, Binding[] bindings, SingleParameterInjector[] injectors) {
          Preconditions.checkArgument(bindings.length == injectors.length);

          this.key = key;
          this.bindings = bindings;
          this.injectors = injectors;
        }
      }

      private Set> dependencies = RealMapBinder.MODULE_DEPENDENCIES;

      private PerKeyData[] perKeyDatas;

      private RealMultimapProvider(Key> mapKey) {
        super(mapKey);
      }

      @Override
      public Set> getDependencies() {
        return dependencies;
      }

      @Override
      protected void doInitialize(InjectorImpl injector, Errors errors) throws ErrorsException {
        @SuppressWarnings({"unchecked", "rawtypes"})
        PerKeyData[] typedPerKeyData =
            new PerKeyData[bindingSelection.getMapBindings().size()];
        perKeyDatas = typedPerKeyData;
        ImmutableSet.Builder> dependenciesBuilder = ImmutableSet.builder();
        List> dependenciesForKey = Lists.newArrayList();
        int i = 0;
        for (Map.Entry>> entry :
            bindingSelection.getMultimapBindings().entrySet()) {
          // Clear the list of dependencies because we're reusing it for each different key
          dependenciesForKey.clear();

          Set> bindings = entry.getValue();
          @SuppressWarnings({"unchecked", "rawtypes"})
          Binding[] typedBindings = new Binding[bindings.size()];
          Binding[] bindingsArray = typedBindings;
          int j = 0;
          for (Binding binding : bindings) {
            Dependency dependency = Dependency.get(binding.getKey());
            dependenciesBuilder.add(dependency);
            dependenciesForKey.add(dependency);
            bindingsArray[j] = binding;
            j++;
          }

          @SuppressWarnings("unchecked")
          SingleParameterInjector[] injectors =
              (SingleParameterInjector[])
                  injector.getParametersInjectors(dependenciesForKey, errors);

          perKeyDatas[i] = new PerKeyData<>(entry.getKey(), bindingsArray, injectors);
          i++;
        }

        dependencies = dependenciesBuilder.build();
      }

      @Override
      protected Map> doProvision(InternalContext context, Dependency dependency)
          throws InternalProvisionException {
        ImmutableMap.Builder> resultBuilder = ImmutableMap.builder();

        for (PerKeyData perKeyData : perKeyDatas) {
          ImmutableSet.Builder bindingsBuilder = ImmutableSet.builder();
          SingleParameterInjector[] injectors = perKeyData.injectors;
          for (int i = 0; i < injectors.length; i++) {
            SingleParameterInjector injector = injectors[i];
            V value = injector.inject(context);

            if (value == null) {
              throw createNullValueException(perKeyData.key, perKeyData.bindings[i]);
            }

            bindingsBuilder.add(value);
          }

          resultBuilder.put(perKeyData.key, bindingsBuilder.build());
        }

        return resultBuilder.build();
      }
    }
  }

  /** A factory for a {@code Map.Entry>}. */
  // VisibleForTesting
  static final class ProviderMapEntry
      extends InternalProviderInstanceBindingImpl.Factory>> {
    private final K key;
    private final Key valueKey;
    private Map.Entry> entry;

    ProviderMapEntry(K key, Key valueKey) {
      super(InitializationTiming.EAGER);
      this.key = key;
      this.valueKey = valueKey;
    }

    @Override
    public Set> getDependencies() {
      // The dependencies are Key>
      return ImmutableSet.>of(Dependency.get(getKeyOfProvider(valueKey)));
    }

    @Override
    void initialize(InjectorImpl injector, Errors errors) {
      Binding valueBinding = injector.getExistingBinding(valueKey);
      entry = Maps.immutableEntry(key, valueBinding.getProvider());
    }

    @Override
    protected Map.Entry> doProvision(
        InternalContext context, Dependency dependency) {
      return entry;
    }

    K getKey() {
      return key;
    }

    Key getValueKey() {
      return valueKey;
    }

    @Override
    public boolean equals(Object obj) {
      if (obj instanceof ProviderMapEntry) {
        ProviderMapEntry o = (ProviderMapEntry) obj;
        return key.equals(o.key) && valueKey.equals(o.valueKey);
      }
      return false;
    }

    @Override
    public int hashCode() {
      return Objects.hashCode(key, valueKey);
    }

    @Override
    public String toString() {
      return "ProviderMapEntry(" + key + ", " + valueKey + ")";
    }
  }

  /** A base class for ProviderWithDependencies that need equality based on a specific object. */
  private abstract static class RealMapBinderProviderWithDependencies
      extends InternalProviderInstanceBindingImpl.Factory
 {
    final BindingSelection bindingSelection;

    private RealMapBinderProviderWithDependencies(BindingSelection bindingSelection) {
      // While MapBinders only depend on bindings created in modules so we could theoretically
      // initialize eagerly, they also depend on
      // 1. findBindingsByType returning results
      // 2. being able to call BindingImpl.acceptTargetVisitor
      // neither of those is available during eager initialization, so we use DELAYED
      super(InitializationTiming.DELAYED);

      this.bindingSelection = bindingSelection;
    }

    @Override
    final void initialize(InjectorImpl injector, Errors errors) throws ErrorsException {
      if (bindingSelection.tryInitialize(injector, errors)) {
        doInitialize(injector, errors);
      }
    }

    /**
     * Initialize the factory. BindingSelection is guaranteed to be initialized at this point and
     * this will be called prior to any provisioning.
     */
    protected abstract void doInitialize(InjectorImpl injector, Errors errors)
        throws ErrorsException;

    @Override
    public boolean equals(Object obj) {
      return obj != null
          && this.getClass() == obj.getClass()
          && bindingSelection.equals(
              ((RealMapBinderProviderWithDependencies) obj).bindingSelection);
    }

    @Override
    public int hashCode() {
      return bindingSelection.hashCode();
    }
  }

  /**
   * A base class for ProviderWithDependencies that need equality based on a specific object.
   *
   * 
This differs from {@link RealMapBinderProviderWithDependencies} in that it gets the {@code
   * bindingSelection} from the injector at initialization time, rather than in the constructor.
   * This is done to allow all the providers to operate on the same instance of the {@link
   * BindingSelection}.
   */
  private abstract static class RealMultimapBinderProviderWithDependencies
      extends InternalProviderInstanceBindingImpl.Factory {
    final Key> mapKey;
    BindingSelection bindingSelection;

    private RealMultimapBinderProviderWithDependencies(Key> mapKey) {
      // While MapBinders only depend on bindings created in modules so we could theoretically
      // initialize eagerly, they also depend on
      // 1. findBindingsByType returning results
      // 2. being able to call BindingImpl.acceptTargetVisitor
      // neither of those is available during eager initialization, so we use DELAYED
      super(InitializationTiming.DELAYED);

      this.mapKey = mapKey;
    }

    /**
     * This will get the authoritative {@link BindingSelection} from the map provider. This
     * guarantees that everyone has the same instance of the bindingSelection and sees consistent
     * state.
     */
    @Override
    final void initialize(InjectorImpl injector, Errors errors) throws ErrorsException {
      Binding> mapBinding = injector.getExistingBinding(mapKey);
      ProviderInstanceBinding> providerInstanceBinding =
          (ProviderInstanceBinding>) mapBinding;
      @SuppressWarnings("unchecked")
      ExtensionRealMapProvider mapProvider =
          (ExtensionRealMapProvider) providerInstanceBinding.getUserSuppliedProvider();

      this.bindingSelection = mapProvider.getBindingSelection();

      if (bindingSelection.tryInitialize(injector, errors)) {
        doInitialize(injector, errors);
      }
    }

    /**
     * Initialize the factory. BindingSelection is guaranteed to be initialized at this point and
     * this will be called prior to any provisioning.
     */
    abstract void doInitialize(InjectorImpl injector, Errors errors) throws ErrorsException;

    @Override
    public boolean equals(Object obj) {
      return obj != null
          && this.getClass() == obj.getClass()
          && mapKey.equals(((RealMultimapBinderProviderWithDependencies) obj).mapKey);
    }

    @Override
    public int hashCode() {
      return mapKey.hashCode();
    }
  }

  private static  InternalProvisionException createNullValueException(
      K key, Binding binding) {
    return InternalProvisionException.create(
        ErrorId.NULL_VALUE_IN_MAP,
        "Map injection failed due to null value for key \"%s\", bound at: %s",
        key,
        binding.getSource());
  }
}