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