content/renderer/pepper/pepper_try_catch.h

   1 // Copyright 2014 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 CONTENT_RENDERER_PEPPER_PEPPER_TRY_CATCH_H_
   6 #define CONTENT_RENDERER_PEPPER_PEPPER_TRY_CATCH_H_
   7
   8 #include "base/basictypes.h"
   9 #include "content/common/content_export.h"
  10 #include "content/renderer/pepper/v8_var_converter.h"
  11 #include "ppapi/c/pp_var.h"
  12 #include "ppapi/shared_impl/scoped_pp_var.h"
  13 #include "v8/include/v8.h"
  14
  15 namespace content {
  16
  17 class PepperPluginInstanceImpl;
  18
  19 // Base class for scripting TryCatch helpers.
  20 class CONTENT_EXPORT PepperTryCatch {
  21  public:
  22   // PepperTryCatch objects should only be used as stack variables. This object
  23   // takes a reference on the given PepperPluginInstanceImpl.
  24   PepperTryCatch(PepperPluginInstanceImpl* instance,
  25                  V8VarConverter::AllowObjectVars convert_objects);
  26   virtual ~PepperTryCatch();
  27
  28   virtual void SetException(const char* message) = 0;
  29   virtual bool HasException() = 0;
  30   // Gets the context to execute scripts in.
  31   virtual v8::Handle<v8::Context> GetContext() = 0;
  32
  33   // Convenience functions for doing conversions to/from V8 values and sets an
  34   // exception if there is an error in the conversion.
  35   v8::Handle<v8::Value> ToV8(PP_Var var);
  36   ppapi::ScopedPPVar FromV8(v8::Handle<v8::Value> v8_value);
  37
  38  protected:
  39   // Make sure that |instance_| is alive for the lifetime of PepperTryCatch.
  40   // PepperTryCatch is used mostly in Pepper scripting code, where it can be
  41   // possible to enter JavaScript synchronously which can cause the plugin to
  42   // be deleted.
  43   //
  44   // Note that PepperTryCatch objects should only ever be on the stack, so this
  45   // shouldn't keep the instance around for too long.
  46   scoped_refptr<PepperPluginInstanceImpl> instance_;
  47
  48   // Whether To/FromV8 should convert object vars. If set to
  49   // kDisallowObjectVars, an exception should be set if they are encountered
  50   // during conversion.
  51   V8VarConverter::AllowObjectVars convert_objects_;
  52 };
  53
  54 // Catches var exceptions and emits a v8 exception.
  55 class PepperTryCatchV8 : public PepperTryCatch {
  56  public:
  57   PepperTryCatchV8(PepperPluginInstanceImpl* instance,
  58                    V8VarConverter::AllowObjectVars convert_objects,
  59                    v8::Isolate* isolate);
  60   virtual ~PepperTryCatchV8();
  61
  62   bool ThrowException();
  63   void ThrowException(const char* message);
  64   PP_Var* exception() { return &exception_; }
  65
  66   // PepperTryCatch
  67   virtual void SetException(const char* message) override;
  68   virtual bool HasException() override;
  69   virtual v8::Handle<v8::Context> GetContext() override;
  70
  71  private:
  72   PP_Var exception_;
  73
  74   DISALLOW_COPY_AND_ASSIGN(PepperTryCatchV8);
  75 };
  76
  77 // Catches v8 exceptions and emits a var exception.
  78 class PepperTryCatchVar : public PepperTryCatch {
  79  public:
  80   // The PP_Var exception will be placed in |exception|. The user of this class
  81   // is responsible for managing the lifetime of the exception. It is valid to
  82   //  pass NULL for |exception| in which case no exception will be set.
  83   PepperTryCatchVar(PepperPluginInstanceImpl* instance,
  84                     PP_Var* exception);
  85   virtual ~PepperTryCatchVar();
  86
  87   // PepperTryCatch
  88   virtual void SetException(const char* message) override;
  89   virtual bool HasException() override;
  90   virtual v8::Handle<v8::Context> GetContext() override;
  91
  92  private:
  93   // Code which uses PepperTryCatchVar doesn't typically have a HandleScope,
  94   // make one for them. Note that this class is always allocated on the stack.
  95   v8::HandleScope handle_scope_;
  96
  97   v8::Handle<v8::Context> context_;
  98
  99   v8::TryCatch try_catch_;
 100
 101   PP_Var* exception_;
 102   bool exception_is_set_;
 103
 104   DISALLOW_COPY_AND_ASSIGN(PepperTryCatchVar);
 105 };
 106
 107 }  // namespace content
 108
 109 #endif  // CONTENT_RENDERER_PEPPER_PEPPER_TRY_CATCH_H_