ppapi/shared_impl/scoped_pp_var.h

   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_SHARED_IMPL_SCOPED_PP_VAR_H_
   6 #define PPAPI_SHARED_IMPL_SCOPED_PP_VAR_H_
   7
   8 #include <stdlib.h>
   9
  10 #include "base/macros.h"
  11 #include "ppapi/c/pp_var.h"
  12 #include "ppapi/shared_impl/ppapi_shared_export.h"
  13
  14 namespace ppapi {
  15
  16 class PPAPI_SHARED_EXPORT ScopedPPVar {
  17  public:
  18   struct PassRef {};
  19
  20   ScopedPPVar();
  21
  22   // Takes one reference to the given var.
  23   explicit ScopedPPVar(const PP_Var& v);
  24
  25   // Assumes responsibility for one ref that the var already has.
  26   ScopedPPVar(const PassRef&, const PP_Var& v);
  27
  28   // Implicit copy constructor allowed.
  29   ScopedPPVar(const ScopedPPVar& other);
  30
  31   ~ScopedPPVar();
  32
  33   ScopedPPVar& operator=(const PP_Var& r);
  34   ScopedPPVar& operator=(const ScopedPPVar& other) {
  35     return operator=(other.var_);
  36   }
  37
  38   const PP_Var& get() const { return var_; }
  39
  40   // Returns the PP_Var, passing the reference to the caller. This class
  41   // will no longer hold the var.
  42   PP_Var Release();
  43
  44  private:
  45   PP_Var var_;
  46 };
  47
  48 // An array of PP_Vars which will be deallocated and have their references
  49 // decremented when they go out of scope.
  50 class PPAPI_SHARED_EXPORT ScopedPPVarArray {
  51  public:
  52   struct PassPPBMemoryAllocatedArray {};
  53
  54   // Assumes responsibility for one ref of each of the vars in the array as
  55   // well as the array memory allocated by PPB_Memory_Dev.
  56   // TODO(raymes): Add compatibility for arrays allocated with C++ "new".
  57   ScopedPPVarArray(const PassPPBMemoryAllocatedArray&,
  58                    PP_Var* array,
  59                    size_t size);
  60
  61   explicit ScopedPPVarArray(size_t size);
  62   ~ScopedPPVarArray();
  63
  64   // Passes ownership of the vars and the underlying array memory to the caller.
  65   // Note that the memory has been allocated with PPB_Memory_Dev.
  66   PP_Var* Release(const PassPPBMemoryAllocatedArray&);
  67
  68   PP_Var* get() { return array_; }
  69   size_t size() { return size_; }
  70
  71   // Takes a ref to |var|. The refcount of the existing var will be decremented.
  72   void Set(size_t index, const ScopedPPVar& var);
  73   const PP_Var& operator[](size_t index) { return array_[index]; }
  74
  75  private:
  76   // TODO(raymes): Consider supporting copy/assign.
  77   DISALLOW_COPY_AND_ASSIGN(ScopedPPVarArray);
  78
  79   PP_Var* array_;
  80   size_t size_;
  81 };
  82
  83 }  // namespace ppapi
  84
  85 #endif  // PPAPI_SHARED_IMPL_SCOPED_PP_VAR_H_