/*
 * Copyright (C) 2013 Google Inc.
 *
 * 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.inject.spi;

import com.google.common.base.Preconditions;
import com.google.common.collect.ImmutableList;
import com.google.inject.Module;
import com.google.inject.internal.util.StackTraceElements;
import com.google.inject.internal.util.StackTraceElements.InMemoryStackTraceElement;
import java.util.List;

Associated to a module, provides the module class name, the parent module source, and the call stack that ends just before the module configure(Binder) method invocation. /**
 * Associated to a {@link Module module}, provides the module class name, the parent module {@link
 * ModuleSource source}, and the call stack that ends just before the module {@link
 * Module#configure(Binder) configure(Binder)} method invocation.
 */
final class ModuleSource {

  
The class name of module that this ModuleSource associated to. /** The class name of module that this {@link ModuleSource} associated to. */
  private final String moduleClassName;

  
The parent module source. /** The parent {@link ModuleSource module source}. */
  private final ModuleSource parent;

  
The chunk of call stack that starts from the parent module 
configure(Binder) call and ends just before the module 
configure(Binder) method invocation. For a module without a parent module the chunk starts from the bottom of call stack. The array is non-empty if stack trace collection is on. /**
   * The chunk of call stack that starts from the parent module {@link Module#configure(Binder)
   * configure(Binder)} call and ends just before the module {@link Module#configure(Binder)
   * configure(Binder)} method invocation. For a module without a parent module the chunk starts
   * from the bottom of call stack. The array is non-empty if stack trace collection is on.
   */
  private final InMemoryStackTraceElement[] partialCallStack;

  
Creates a new ModuleSource with a null parent. 
Params:
moduleClass – the corresponding module
partialCallStack – the chunk of call stack that starts from the parent module configure(Binder) call and ends just before the module configure(Binder) method invocation/**
   * Creates a new {@link ModuleSource} with a {@literal null} parent.
   *
   * @param moduleClass the corresponding module
   * @param partialCallStack the chunk of call stack that starts from the parent module {@link
   *     Module#configure(Binder) configure(Binder)} call and ends just before the module {@link
   *     Module#configure(Binder) configure(Binder)} method invocation
   */
  ModuleSource(Class<?> moduleClass, StackTraceElement[] partialCallStack) {
    this(null, moduleClass, partialCallStack);
  }

  
Creates a new ModuleSource Object. 
Params:
parent – the parent module source
moduleClass – the corresponding module
partialCallStack – the chunk of call stack that starts from the parent module configure(Binder) call and ends just before the module configure(Binder) method invocation/**
   * Creates a new {@link ModuleSource} Object.
   *
   * @param parent the parent module {@link ModuleSource source}
   * @param moduleClass the corresponding module
   * @param partialCallStack the chunk of call stack that starts from the parent module {@link
   *     Module#configure(Binder) configure(Binder)} call and ends just before the module {@link
   *     Module#configure(Binder) configure(Binder)} method invocation
   */
  private ModuleSource(
      /* @Nullable */ ModuleSource parent,
      Class<?> moduleClass,
      StackTraceElement[] partialCallStack) {
    Preconditions.checkNotNull(moduleClass, "module cannot be null.");
    Preconditions.checkNotNull(partialCallStack, "partialCallStack cannot be null.");
    this.parent = parent;
    this.moduleClassName = moduleClass.getName();
    this.partialCallStack = StackTraceElements.convertToInMemoryStackTraceElement(partialCallStack);
  }

  
Returns the corresponding module class name.
See Also:
getName.getName()/**
   * Returns the corresponding module class name.
   *
   * @see Class#getName()
   */
  String getModuleClassName() {
    return moduleClassName;
  }

  
Returns the chunk of call stack that starts from the parent module configure(Binder) call and ends just before the module configure(Binder) method invocation. The return array is non-empty only if stack trace collection is on. /**
   * Returns the chunk of call stack that starts from the parent module {@link
   * Module#configure(Binder) configure(Binder)} call and ends just before the module {@link
   * Module#configure(Binder) configure(Binder)} method invocation. The return array is non-empty
   * only if stack trace collection is on.
   */
  StackTraceElement[] getPartialCallStack() {
    return StackTraceElements.convertToStackTraceElement(partialCallStack);
  }

  
Returns the size of partial call stack if stack trace collection is on otherwise zero. /** Returns the size of partial call stack if stack trace collection is on otherwise zero. */
  int getPartialCallStackSize() {
    return partialCallStack.length;
  }

  
Creates and returns a child ModuleSource corresponding to the module. 
Params:
moduleClass – the corresponding module
partialCallStack – the chunk of call stack that starts from the parent module configure(Binder) call and ends just before the module configure(Binder) method invocation/**
   * Creates and returns a child {@link ModuleSource} corresponding to the {@link Module module}.
   *
   * @param moduleClass the corresponding module
   * @param partialCallStack the chunk of call stack that starts from the parent module {@link
   *     Module#configure(Binder) configure(Binder)} call and ends just before the module {@link
   *     Module#configure(Binder) configure(Binder)} method invocation
   */
  ModuleSource createChild(Class<?> moduleClass, StackTraceElement[] partialCallStack) {
    return new ModuleSource(this, moduleClass, partialCallStack);
  }

  
Returns the parent module source. /** Returns the parent module {@link ModuleSource source}. */
  ModuleSource getParent() {
    return parent;
  }

  
Returns the class names of modules in this module source. The first element (index 0) is filled by this object getModuleClassName(). The second element is filled by the parent's getModuleClassName() and so on. /**
   * Returns the class names of modules in this module source. The first element (index 0) is filled
   * by this object {@link #getModuleClassName()}. The second element is filled by the parent's
   * {@link #getModuleClassName()} and so on.
   */
  List<String> getModuleClassNames() {
    ImmutableList.Builder<String> classNames = ImmutableList.builder();
    ModuleSource current = this;
    while (current != null) {
      String className = current.moduleClassName;
      classNames.add(className);
      current = current.parent;
    }
    return classNames.build();
  }

  
Returns the size of ModuleSources chain (all parents) that ends at this object. /**
   * Returns the size of {@link ModuleSource ModuleSources} chain (all parents) that ends at this
   * object.
   */
  int size() {
    if (parent == null) {
      return 1;
    }
    return parent.size() + 1;
  }

  
Returns the size of call stack that ends just before the module 
configure(Binder) method invocation (see getStackTrace()). /**
   * Returns the size of call stack that ends just before the module {@link Module#configure(Binder)
   * configure(Binder)} method invocation (see {@link #getStackTrace()}).
   */
  int getStackTraceSize() {
    if (parent == null) {
      return partialCallStack.length;
    }
    return parent.getStackTraceSize() + partialCallStack.length;
  }

  
Returns the full call stack that ends just before the module 
configure(Binder) method invocation. The return array is non-empty if stack trace collection on. /**
   * Returns the full call stack that ends just before the module {@link Module#configure(Binder)
   * configure(Binder)} method invocation. The return array is non-empty if stack trace collection
   * on.
   */
  StackTraceElement[] getStackTrace() {
    int stackTraceSize = getStackTraceSize();
    StackTraceElement[] callStack = new StackTraceElement[stackTraceSize];
    int cursor = 0;
    ModuleSource current = this;
    while (current != null) {
      StackTraceElement[] chunk =
          StackTraceElements.convertToStackTraceElement(current.partialCallStack);
      int chunkSize = chunk.length;
      System.arraycopy(chunk, 0, callStack, cursor, chunkSize);
      current = current.parent;
      cursor = cursor + chunkSize;
    }
    return callStack;
  }
}