Add PPB_VarDictionary_Dev support - part 1.

ppapi/shared_impl/var_value_conversions.cc

+// Copyright (c) 2013 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/shared_impl/var_value_conversions.h"
+
+#include <limits>
+#include <set>
+#include <stack>
+
+#include "base/logging.h"
+#include "base/memory/ref_counted.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/stl_util.h"
+#include "base/values.h"
+#include "ppapi/c/pp_bool.h"
+#include "ppapi/c/pp_stdint.h"
+#include "ppapi/shared_impl/dictionary_var.h"
+#include "ppapi/shared_impl/ppapi_globals.h"
+#include "ppapi/shared_impl/scoped_pp_var.h"
+#include "ppapi/shared_impl/var.h"
+#include "ppapi/shared_impl/var_tracker.h"
+
+namespace ppapi {
+
+namespace {
+
+// In CreateValueFromVar(), a stack is used to keep track of conversion progress
+// of array and dictionary vars. VarNode represents elements of that stack.
+struct VarNode {
+  VarNode(const PP_Var& in_var, base::Value* in_value)
+      : var(in_var),
+        value(in_value),
+        sentinel(false) {
+  }
+
+  // This object doesn't hold a reference to it.
+  PP_Var var;
+  // It is not owned by this object.
+  base::Value* value;
+  // When this is set to true for a node in the stack, it means that we have
+  // finished processing the node itself. However, we keep it in the stack as
+  // a sentinel. When it becomes the top element of the stack again, we know
+  // that we have processed all the descendants of this node.
+  bool sentinel;
+};
+
+// In CreateVarFromValue(), a stack is used to keep track of conversion progress
+// of list and dictionary values. ValueNode represents elements of that stack.
+struct ValueNode {
+  ValueNode(const PP_Var& in_var, const base::Value* in_value)
+      : var(in_var),
+        value(in_value) {
+  }
+
+  // This object doesn't hold a reference to it.
+  PP_Var var;
+  // It is not owned by this object.
+  const base::Value* value;
+};
+
+// Helper function for CreateValueFromVar(). It only looks at |var| but not its
+// descendants. The conversion result is stored in |value|. If |var| is array or
+// dictionary, a new node is pushed onto |state|.
+//
+// Returns false on failure.
+bool CreateValueFromVarHelper(const std::set<int64_t>& parent_ids,
+                              const PP_Var& var,
+                              scoped_ptr<base::Value>* value,
+                              std::stack<VarNode>* state) {
+  switch (var.type) {
+    case PP_VARTYPE_UNDEFINED:
+    case PP_VARTYPE_NULL: {
+      value->reset(base::Value::CreateNullValue());
+      return true;
+    }
+    case PP_VARTYPE_BOOL: {
+      value->reset(new base::FundamentalValue(PP_ToBool(var.value.as_bool)));
+      return true;
+    }
+    case PP_VARTYPE_INT32: {
+      value->reset(new base::FundamentalValue(var.value.as_int));
+      return true;
+    }
+    case PP_VARTYPE_DOUBLE: {
+      value->reset(new base::FundamentalValue(var.value.as_double));
+      return true;
+    }
+    case PP_VARTYPE_STRING: {
+      StringVar* string_var = StringVar::FromPPVar(var);
+      if (!string_var)
+        return false;
+
+      value->reset(new base::StringValue(string_var->value()));
+      return true;
+    }
+    case PP_VARTYPE_OBJECT: {
+      return false;
+    }
+    case PP_VARTYPE_ARRAY: {
+      // TODO(yzshen): Implement it once array var is supported.
+      return false;
+    }
+    case PP_VARTYPE_DICTIONARY: {
+      if (ContainsKey(parent_ids, var.value.as_id)) {
+        // A circular reference is found.
+        return false;
+      }
+
+      value->reset(new base::DictionaryValue());
+      state->push(VarNode(var, value->get()));
+      return true;
+    }
+    case PP_VARTYPE_ARRAY_BUFFER: {
+      ArrayBufferVar* array_buffer = ArrayBufferVar::FromPPVar(var);
+      if (!array_buffer)
+        return false;
+
+      base::BinaryValue* binary_value =
+          base::BinaryValue::CreateWithCopiedBuffer(
+              static_cast<const char*>(array_buffer->Map()),
+              array_buffer->ByteLength());
+      array_buffer->Unmap();
+      value->reset(binary_value);
+      return true;
+    }
+  }
+  NOTREACHED();
+  return false;
+}
+
+// Helper function for CreateVarFromValue(). It only looks at |value| but not
+// its descendants. The conversion result is stored in |var|. If |value| is list
+// or dictionary, a new node is pushed onto |state|.
+//
+// Returns false on failure.
+bool CreateVarFromValueHelper(const base::Value& value,
+                              ScopedPPVar* var,
+                              std::stack<ValueNode>* state) {
+  switch (value.GetType()) {
+    case base::Value::TYPE_NULL: {
+      *var = PP_MakeNull();
+      return true;
+    }
+    case base::Value::TYPE_BOOLEAN: {
+      bool result = false;
+      if (value.GetAsBoolean(&result)) {
+        *var = PP_MakeBool(PP_FromBool(result));
+        return true;
+      }
+      return false;
+    }
+    case base::Value::TYPE_INTEGER: {
+      int result = 0;
+      if (value.GetAsInteger(&result)) {
+        *var = PP_MakeInt32(result);
+        return true;
+      }
+      return false;
+    }
+    case base::Value::TYPE_DOUBLE: {
+      double result = 0;
+      if (value.GetAsDouble(&result)) {
+        *var = PP_MakeDouble(result);
+        return true;
+      }
+      return false;
+    }
+    case base::Value::TYPE_STRING: {
+      std::string result;
+      if (value.GetAsString(&result)) {
+        *var = ScopedPPVar(ScopedPPVar::PassRef(),
+                           StringVar::StringToPPVar(result));
+        return true;
+      }
+      return false;
+    }
+    case base::Value::TYPE_BINARY: {
+      const base::BinaryValue& binary_value =
+          static_cast<const base::BinaryValue&>(value);
+
+      size_t size = binary_value.GetSize();
+      if (size > std::numeric_limits<uint32>::max())
+        return false;
+
+      ScopedPPVar temp(
+          ScopedPPVar::PassRef(),
+          PpapiGlobals::Get()->GetVarTracker()->MakeArrayBufferPPVar(
+              static_cast<uint32>(size), binary_value.GetBuffer()));
+      if (temp.get().type == PP_VARTYPE_ARRAY_BUFFER) {
+        *var = temp;
+        return true;
+      }
+      return false;
+    }
+    case base::Value::TYPE_DICTIONARY: {
+      scoped_refptr<DictionaryVar> dict_var(new DictionaryVar());
+      *var = ScopedPPVar(ScopedPPVar::PassRef(), dict_var->GetPPVar());
+      state->push(ValueNode(var->get(), &value));
+      return true;
+    }
+    case base::Value::TYPE_LIST: {
+      // TODO(yzshen): Add support once array var is supported.
+      return false;
+    }
+  }
+  NOTREACHED();
+  return false;
+}
+
+}  // namespace
+
+base::Value* CreateValueFromVar(const PP_Var& var) {
+  // Used to detect circular references.
+  std::set<int64_t> parent_ids;
+  std::stack<VarNode> state;
+  scoped_ptr<base::Value> root_value;
+
+  if (!CreateValueFromVarHelper(parent_ids, var, &root_value, &state))
+    return NULL;
+
+  while (!state.empty()) {
+    VarNode& top = state.top();
+    if (top.sentinel) {
+      parent_ids.erase(top.var.value.as_id);
+      state.pop();
+    } else if (top.var.type == PP_VARTYPE_DICTIONARY) {
+      parent_ids.insert(top.var.value.as_id);
+      top.sentinel = true;
+
+      DictionaryVar* dict_var = DictionaryVar::FromPPVar(top.var);
+      if (!dict_var)
+        return NULL;
+
+      DCHECK(top.value->GetType() == base::Value::TYPE_DICTIONARY);
+      base::DictionaryValue* dict_value =
+          static_cast<base::DictionaryValue*>(top.value);
+
+      for (DictionaryVar::KeyValueMap::const_iterator iter =
+               dict_var->key_value_map().begin();
+           iter != dict_var->key_value_map().end();
+           ++iter) {
+        // Skip the key-value pair if the value is undefined.
+        if (iter->second.get().type == PP_VARTYPE_UNDEFINED)
+          continue;
+
+        scoped_ptr<base::Value> child_value;
+        if (!CreateValueFromVarHelper(parent_ids, iter->second.get(),
+                                      &child_value, &state)) {
+          return NULL;
+        }
+
+        dict_value->SetWithoutPathExpansion(iter->first, child_value.release());
+      }
+    } else {
+      NOTREACHED();
+      return NULL;
+    }
+  }
+  DCHECK(parent_ids.empty());
+  return root_value.release();
+}
+
+PP_Var CreateVarFromValue(const base::Value& value) {
+  std::stack<ValueNode> state;
+  ScopedPPVar root_var;
+
+  if (!CreateVarFromValueHelper(value, &root_var, &state))
+    return PP_MakeUndefined();
+
+  while (!state.empty()) {
+    ValueNode top = state.top();
+    state.pop();
+
+    if (top.value->GetType() == base::Value::TYPE_DICTIONARY) {
+      const base::DictionaryValue* dict_value =
+          static_cast<const base::DictionaryValue*>(top.value);
+      DictionaryVar* dict_var = DictionaryVar::FromPPVar(top.var);
+      DCHECK(dict_var);
+      for (base::DictionaryValue::Iterator iter(*dict_value);
+           !iter.IsAtEnd();
+           iter.Advance()) {
+        ScopedPPVar child_var;
+        if (!CreateVarFromValueHelper(iter.value(), &child_var, &state) ||
+            !dict_var->SetWithStringKey(iter.key(), child_var.get())) {
+          return PP_MakeUndefined();
+        }
+      }
+    } else {
+      NOTREACHED();
+      return PP_MakeUndefined();
+    }
+  }
+
+  return root_var.Release();
+}
+}  // namespace ppapi
+