1 // Copyright (c) 2012 The Chromium Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #ifndef PPAPI_PROXY_VAR_SERIALIZATION_RULES_H_ 6 #define PPAPI_PROXY_VAR_SERIALIZATION_RULES_H_ 7 8 #include "base/memory/ref_counted.h" 9 #include "ppapi/c/pp_var.h" 10 11 #include <string> 12 13 namespace ppapi { 14 namespace proxy { 15 16 // Encapsulates the rules for serializing and deserializing vars to and from 17 // the local process. The renderer and the plugin process each have separate 18 // bookkeeping rules. 19 class VarSerializationRules : public base::RefCounted<VarSerializationRules> { 20 public: 21 // Caller-owned calls -------------------------------------------------------- 22 // 23 // A caller-owned call is when doing a function call with a "normal" input 24 // argument. The caller has a reference to the var, and the caller is 25 // responsible for freeing that reference. 26 27 // Prepares the given var for sending to the remote process. For object vars, 28 // the returned var will contain the id valid for the host process. 29 // Otherwise, the returned var is valid in the local process. 30 virtual PP_Var SendCallerOwned(const PP_Var& var) = 0; 31 32 // When receiving a caller-owned variable, normally we don't have to do 33 // anything. However, in the case of strings, we need to deserialize the 34 // string from IPC, call the function, and then destroy the temporary string. 35 // These two functions handle that process. 36 // 37 // BeginReceiveCallerOwned takes a var from IPC and returns a new var 38 // representing the input in the local process. 39 // 40 // EndReceiveCallerOwned releases the reference count in the Var tracker for 41 // the object or string that was added to the tracker. (Note, if the recipient 42 // took a reference to the Var, it will remain in the tracker after 43 // EndReceiveCallerOwned). 44 virtual PP_Var BeginReceiveCallerOwned(const PP_Var& var) = 0; 45 virtual void EndReceiveCallerOwned(const PP_Var& var) = 0; 46 47 // Passing refs ------------------------------------------------------------- 48 // 49 // A pass-ref transfer is when ownership of a reference is passed from 50 // one side to the other. Normally, this happens via return values and 51 // output arguments, as for exceptions. The code generating the value 52 // (the function returning it in the case of a return value) will AddRef 53 // the var on behalf of the consumer of the value. Responsibility for 54 // Release is on the consumer (the caller of the function in the case of a 55 // return value). 56 57 // Creates a var in the context of the local process from the given 58 // deserialized var. The input var should be the result of calling 59 // SendPassRef in the remote process. The return value is the var valid in 60 // the host process for object vars. Otherwise, the return value is a var 61 // which is valid in the local process. 62 virtual PP_Var ReceivePassRef(const PP_Var& var) = 0; 63 64 // Prepares a var to be sent to the remote side. One local reference will 65 // be passed to the remote side. Call Begin* before doing the send and End* 66 // after doing the send 67 // 68 // For object vars, the return value from BeginSendPassRef will be the var 69 // valid for the host process. Otherwise, it is a var that is valid in the 70 // local process. This same var must be passed to EndSendPassRef. 71 virtual PP_Var BeginSendPassRef(const PP_Var& var) = 0; 72 virtual void EndSendPassRef(const PP_Var& var) = 0; 73 74 // --------------------------------------------------------------------------- 75 76 virtual void ReleaseObjectRef(const PP_Var& var) = 0; 77 78 protected: 79 VarSerializationRules() {} 80 virtual ~VarSerializationRules() {} 81 82 private: 83 friend class base::RefCounted<VarSerializationRules>; 84 }; 85 86 } // namespace proxy 87 } // namespace ppapi 88 89 #endif // PPAPI_PROXY_VAR_SERIALIZATION_RULES_H_ 90
