text: // Copyright 2012 The Chromium Authors. All rights reserved.
  // Use of this source code is governed by a BSD-style license that can be
  // found in the LICENSE file.
  
  #ifndef IOS_WEB_PUBLIC_WEB_STATE_JS_CRW_JS_INJECTION_MANAGER_H_
  #define IOS_WEB_PUBLIC_WEB_STATE_JS_CRW_JS_INJECTION_MANAGER_H_
  
  #import <Foundation/Foundation.h>
  
  #import "ios/web/public/web_state/js/crw_js_injection_evaluator.h"
  
  @class CRWJSInjectionReceiver;
  
  // This class defines the abstract interface for managing JavaScript
  // Injection into a UIWebView.
  @interface CRWJSInjectionManager : NSObject
  
  // Designated initializer. Initializes the object with the |receiver|.
  - (id)initWithReceiver:(CRWJSInjectionReceiver*)receiver;
  
  // The array of |CRWJSInjectionManager| this class depends on. Default to be
  // empty array. Note circular dependency is not allowed, which will cause stack
  // overflow in dependency related computation such as -allDependencies.
  - (NSArray*)directDependencies;
  
  // Returns a list of all the CRWJSInjectionManagers required by this manager,
  // that is, this manager and the managers it directly or indirectly depends on.
  // The list is ordered in such a way that any CRWJSInjectionManager in the list
  // only depends on those appear before it in the list.
  - (NSArray*)allDependencies;
  
  // Returns whether JavaScript has already been injected into the receiver.
  - (BOOL)hasBeenInjected;
  
  // Injects JavaScript at |self.scriptPath| into the receiver object if it is
  // missing. It also injects the dependencies' JavaScript if they are missing.
  - (void)inject;
  
  // Returns an autoreleased string that is the JavaScript to be injected into
  // the receiver object including any JavaScript for all specified dependencies.
  - (NSString*)injectionContentIncludingDependencies;
  
  // Evaluates the provided JavaScript expression, slightly deferred. Designed for
  // scripts where the chance of crwebinvoke:// being triggered indirectly is
  // high, and that aren't required to return a value.
  - (void)deferredEvaluate:(NSString*)script;
  
  // Evaluate the provided JavaScript asynchronously calling completionHandler
  // after execution. The |completionHandler| can be nil.
  - (void)evaluate:(NSString*)script
      stringResultHandler:(web::JavaScriptCompletion)completionHandler;
  
  @end
  
  @interface CRWJSInjectionManager (ProtectedMethods)
  
  // The injection receiver used to evaluate JavaScript.
  - (CRWJSInjectionReceiver*)receiver;
  
  // Path for the resource in the application bundle of type "js" that needs to
  // injected for this manager.
  // Subclasses must override this method to return the path to the JavaScript
  // that needs to be injected.
  - (NSString*)scriptPath;
  
  // The JavaScript function that returns the JavaScript constant of undefined
  // if the JavaScript has not been injected. Default to be nil. Subclasses
  // should override this if their script should only be injected into a page
  // once.
  - (NSString*)presenceBeacon;
  
  // Returns the content that should be injected. This is called every time
  // injection content is needed; by default is uses a cached copy of
  // staticInjectionContent.
  // Subclasses should override this only if the content needs to be dynamic
  // rather than cached, otherwise they should override staticInjectionContent.
  - (NSString*)injectionContent;
  
  // Returns an autoreleased string that is the JavaScript to be injected into
  // the receiver object. By default this returns the contents of the script file;
  // subclasses can override this if they need to get a static script from some
  // other source.
  // The return value from this method will be cached; if dynamic script content
  // is necessary, override injectionContent instead.
  - (NSString*)staticInjectionContent;
  
  // Injects dependencies if they are missing.
  - (void)injectDependenciesIfMissing;
  
  @end
  
  #endif  // IOS_WEB_PUBLIC_WEB_STATE_JS_CRW_JS_INJECTION_MANAGER_H_
  