[PPAPI] pp::Var uses the latest version of the PPB_Var API.

ppapi/cpp/var.cc

 // Copyright (c) 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.
 
 #include "ppapi/cpp/var.h"
 
 #include <stdio.h>
 #include <string.h>
 
 #include <algorithm>
@@ skipping 21 matching lines @@
   return PPB_VAR_INTERFACE_1_0;
 }
 
 // Technically you can call AddRef and Release on any Var, but it may involve
 // cross-process calls depending on the plugin. This is an optimization so we
 // only do refcounting on the necessary objects.
 inline bool NeedsRefcounting(const PP_Var& var) {
   return var.type > PP_VARTYPE_DOUBLE;
 }
 
-// This helper function detects whether PPB_Var version 1.1 is available. If so,
-// it uses it to create a PP_Var for the given string. Otherwise it falls back
-// to PPB_Var version 1.0.
+// This helper function uses the latest available version of VarFromUtf8. Note
+// that version 1.0 of this method has a different API to later versions.
 PP_Var VarFromUtf8Helper(const char* utf8_str, uint32_t len) {
   if (has_interface<PPB_Var_1_1>()) {
     return get_interface<PPB_Var_1_1>()->VarFromUtf8(utf8_str, len);
   } else if (has_interface<PPB_Var_1_0>()) {
     return get_interface<PPB_Var_1_0>()->VarFromUtf8(Module::Get()->pp_module(),
                                                      utf8_str,
                                                      len);
   } else {
     return PP_MakeNull();
   }
 }
 
+// This helper function uses the latest available version of AddRef.
+// Returns true on success, false if no appropriate interface was available.
+bool AddRefHelper(const PP_Var& var) {
+  if (has_interface<PPB_Var_1_1>()) {
+    get_interface<PPB_Var_1_1>()->AddRef(var);
+    return true;
+  } else if (has_interface<PPB_Var_1_0>()) {
+    get_interface<PPB_Var_1_0>()->AddRef(var);
+    return true;
+  } else {
+    return false;
+  }

[dmichael (off chromium), 2014/02/10 22:53:08]

per the style guide (as mentioned in https://codereview.chromium.org/158563002/
), I think this final condition shouldn't be in an else. (Same elsewhere)

[Matt Giuca, 2014/02/10 23:58:10]

Done.

+}
+
+// This helper function uses the latest available version of Release.
+// Returns true on success, false if no appropriate interface was available.
+bool ReleaseHelper(const PP_Var& var) {
+  if (has_interface<PPB_Var_1_1>()) {
+    get_interface<PPB_Var_1_1>()->Release(var);
+    return true;
+  } else if (has_interface<PPB_Var_1_0>()) {
+    get_interface<PPB_Var_1_0>()->Release(var);
+    return true;
+  } else {
+    return false;
+  }
+}
+
 }  // namespace
 
 Var::Var() {
   memset(&var_, 0, sizeof(var_));
   var_.type = PP_VARTYPE_UNDEFINED;
   is_managed_ = true;
 }
 
 Var::Var(Null) {
   memset(&var_, 0, sizeof(var_));
@@ skipping 32 matching lines @@
   var_ = VarFromUtf8Helper(utf8_str.c_str(),
                            static_cast<uint32_t>(utf8_str.size()));
   is_managed_ = true;
 }
 
 
 Var::Var(const PP_Var& var) {
   var_ = var;
   is_managed_ = true;
   if (NeedsRefcounting(var_)) {
-    if (has_interface<PPB_Var_1_0>())
-      get_interface<PPB_Var_1_0>()->AddRef(var_);
-    else
+    if (!AddRefHelper(var_))
       var_.type = PP_VARTYPE_NULL;
   }
 }
 
 Var::Var(const Var& other) {
   var_ = other.var_;
   is_managed_ = true;
   if (NeedsRefcounting(var_)) {
-    if (has_interface<PPB_Var_1_0>())
-      get_interface<PPB_Var_1_0>()->AddRef(var_);
-    else
+    if (!AddRefHelper(var_))
       var_.type = PP_VARTYPE_NULL;
   }
 }
 
 Var::~Var() {
-  if (NeedsRefcounting(var_) &&
-      is_managed_ &&
-      has_interface<PPB_Var_1_0>())
-    get_interface<PPB_Var_1_0>()->Release(var_);
+  if (NeedsRefcounting(var_) && is_managed_)
+    ReleaseHelper(var_);
 }
 
 Var& Var::operator=(const Var& other) {
   // Early return for self-assignment. Note however, that two distinct vars
   // can refer to the same object, so we still need to be careful about the
   // refcounting below.
   if (this == &other)
     return *this;
 
   // Be careful to keep the ref alive for cases where we're assigning an
   // object to itself by addrefing the new one before releasing the old one.
   bool old_is_managed = is_managed_;
   is_managed_ = true;
   if (NeedsRefcounting(other.var_)) {
-    // Assume we already has_interface<PPB_Var_1_0> for refcounted vars or else
-    // we couldn't have created them in the first place.
-    get_interface<PPB_Var_1_0>()->AddRef(other.var_);
+    AddRefHelper(other.var_);
   }
   if (NeedsRefcounting(var_) && old_is_managed)
-    get_interface<PPB_Var_1_0>()->Release(var_);
+    ReleaseHelper(var_);
 
   var_ = other.var_;
   return *this;
 }
 
 bool Var::operator==(const Var& other) const {
   if (var_.type != other.var_.type)
     return false;
   switch (var_.type) {
     case PP_VARTYPE_UNDEFINED:
@@ skipping 43 matching lines @@
   PP_NOTREACHED();
   return 0.0;
 }
 
 std::string Var::AsString() const {
   if (!is_string()) {
     PP_NOTREACHED();
     return std::string();
   }
 
-  if (!has_interface<PPB_Var_1_0>())
+  uint32_t len;
+  const char* str;
+  if (has_interface<PPB_Var_1_1>())
+    str = get_interface<PPB_Var_1_1>()->VarToUtf8(var_, &len);
+  else if (has_interface<PPB_Var_1_0>())
+    str = get_interface<PPB_Var_1_0>()->VarToUtf8(var_, &len);
+  else
     return std::string();
-  uint32_t len;
-  const char* str = get_interface<PPB_Var_1_0>()->VarToUtf8(var_, &len);
   return std::string(str, len);
 }
 
 std::string Var::DebugString() const {
   char buf[256];
   if (is_undefined()) {
     snprintf(buf, sizeof(buf), "Var(UNDEFINED)");
   } else if (is_null()) {
     snprintf(buf, sizeof(buf), "Var(NULL)");
   } else if (is_bool()) {
@@ skipping 20 matching lines @@
     snprintf(buf, sizeof(buf), "Var(DICTIONARY)");
   } else if (is_array_buffer()) {
     snprintf(buf, sizeof(buf), "Var(ARRAY_BUFFER)");
   } else {
     buf[0] = '\0';
   }
   return buf;
 }
 
 }  // namespace pp