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 <algorithm>
+#include <limits>
+#include <vector>
+
+#include "base/logging.h"
+#include "base/memory/ref_counted.h"
+#include "base/memory/scoped_ptr.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 {
+
+base::Value* CreateValueFromVarImpl(const PP_Var& var,
+                                    std::vector<int64_t>* parent_ids) {
+  switch (var.type) {
+    case PP_VARTYPE_UNDEFINED: {
+      return NULL;
+    }
+    case PP_VARTYPE_NULL: {
+      return base::Value::CreateNullValue();
+    }
+    case PP_VARTYPE_BOOL: {
+      return new base::FundamentalValue(PP_ToBool(var.value.as_bool));
+    }
+    case PP_VARTYPE_INT32: {
+      return new base::FundamentalValue(var.value.as_int);
+    }
+    case PP_VARTYPE_DOUBLE: {
+      return new base::FundamentalValue(var.value.as_double);
+    }
+    case PP_VARTYPE_STRING: {
+      StringVar* string_var = StringVar::FromPPVar(var);
+      if (!string_var)
+        return NULL;
+      return new base::StringValue(string_var->value());
+    }
+    case PP_VARTYPE_OBJECT: {
+      return NULL;
+    }
+    case PP_VARTYPE_ARRAY: {
+      if (std::find(parent_ids->begin(), parent_ids->end(), var.value.as_id) !=
+              parent_ids->end()) {

[dmichael (off chromium), 2013/03/05 22:01:03]

So the conversion is O(n^2). You could drop it to O(n) expected time by also
having a hash set. Not sure if it's worth it in practice, though.

[yzshen1, 2013/03/14 05:38:21]

Done. I changed it to a set.

(I think it should be better than O(n^2) though. Because |parent_ids| only
contains the ancestors of the current node, so the size of |parent_ids| should
be something like O(lg(n)) in average cases, and conversion will be O(nlg(n)).)

[dmichael (off chromium), 2013/03/15 17:35:48]

O(n^2) worst-case for a line of Object->Child->ChildOfChild->ChildOfChildOfChild
etc.
Fair enough.

[yzshen1, 2013/03/15 22:56:49]

Right. That is true.

+        // A circular reference is found.
+        return NULL;
+      }
+
+      scoped_ptr<base::ListValue> list_value(new base::ListValue());
+      parent_ids->push_back(var.value.as_id);
+
+      // TODO(yzshen): Implement it once array var is supported.
+
+      parent_ids->pop_back();
+      return list_value.release();
+    }
+    case PP_VARTYPE_DICTIONARY: {
+      if (std::find(parent_ids->begin(), parent_ids->end(), var.value.as_id) !=
+              parent_ids->end()) {
+        // A circular reference is found.
+        return NULL;
+      }
+
+      DictionaryVar* dict_var = DictionaryVar::FromPPVar(var);
+      if (!dict_var)
+        return NULL;
+
+      scoped_ptr<base::DictionaryValue> dict_value(new base::DictionaryValue());
+      parent_ids->push_back(var.value.as_id);
+
+      for (DictionaryVar::KeyValueMap::const_iterator iter =
+               dict_var->key_value_map().begin();
+           iter != dict_var->key_value_map().end(); ++iter) {
+        base::Value* value = CreateValueFromVarImpl(iter->second.get(),
+                                                    parent_ids);

[dmichael (off chromium), 2013/03/05 22:01:03]

If a plugin creates a really deep object, they can induce stack overflow here.
It might be better to have a work-queue kind of approach rather than recursion.

[yzshen1, 2013/03/14 05:38:21]

Yeah, this is a good idea.
Thanks!
On 2013/03/05 22:01:03, dmichael wrote:

+        if (!value) {
+          parent_ids->pop_back();
+          return NULL;
+        }
+
+        dict_value->SetWithoutPathExpansion(iter->first, value);
+      }
+
+      parent_ids->pop_back();
+      return dict_value.release();
+    }
+    case PP_VARTYPE_ARRAY_BUFFER: {
+      ArrayBufferVar* array_buffer = ArrayBufferVar::FromPPVar(var);
+      if (!array_buffer)
+        return NULL;
+
+      base::BinaryValue* binary_value =
+          base::BinaryValue::CreateWithCopiedBuffer(
+              static_cast<const char*>(array_buffer->Map()),
+              array_buffer->ByteLength());
+      array_buffer->Unmap();
+      return binary_value;
+    }
+  }
+  NOTREACHED();
+  return NULL;
+}
+
+}  // namespace
+
+base::Value* CreateValueFromVar(const PP_Var& var) {
+  std::vector<int64_t> parent_ids;
+  base::Value* result = CreateValueFromVarImpl(var, &parent_ids);
+  DCHECK(parent_ids.empty());
+  return result;
+}
+
+PP_Var CreateVarFromValue(const base::Value& value) {
+  switch (value.GetType()) {
+    case base::Value::TYPE_NULL: {
+      return PP_MakeNull();
+    }
+    case base::Value::TYPE_BOOLEAN: {
+      bool result = false;
+      if (value.GetAsBoolean(&result))
+        return PP_MakeBool(PP_FromBool(result));
+      else
+        return PP_MakeUndefined();
+    }
+    case base::Value::TYPE_INTEGER: {
+      int result = 0;
+      if (value.GetAsInteger(&result))
+        return PP_MakeInt32(result);
+      else
+        return PP_MakeUndefined();
+    }
+    case base::Value::TYPE_DOUBLE: {
+      double result = 0;
+      if (value.GetAsDouble(&result))
+        return PP_MakeDouble(result);
+      else
+        return PP_MakeUndefined();
+    }
+    case base::Value::TYPE_STRING: {
+      std::string result;
+      if (value.GetAsString(&result))
+        return StringVar::StringToPPVar(result);
+      else
+        return PP_MakeUndefined();
+    }
+    case base::Value::TYPE_BINARY: {

[dmichael (off chromium), 2013/03/05 22:01:03]

nit: It might be nice to order these cases the same as the order in
CreateValueFromVarImpl

[yzshen1, 2013/03/14 05:38:21]

I ordered them according to the enum type definition. 
On 2013/03/05 22:01:03, dmichael wrote:

+      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 PP_MakeUndefined();
+
+      return PpapiGlobals::Get()->GetVarTracker()->MakeArrayBufferPPVar(
+          static_cast<uint32>(size), binary_value.GetBuffer());
+    }
+    case base::Value::TYPE_DICTIONARY: {
+      const base::DictionaryValue& dict_value =
+          static_cast<const base::DictionaryValue&>(value);
+
+      scoped_refptr<DictionaryVar> dict_var(new DictionaryVar());
+
+      for (base::DictionaryValue::Iterator iter(dict_value); !iter.IsAtEnd();

[dmichael (off chromium), 2013/03/05 22:01:03]

nit: I prefer each statement in the for to be on its own line if they don't fit
on 1.

[yzshen1, 2013/03/14 05:38:21]

Done.

+           iter.Advance()) {
+        ScopedPPVar child_var(ScopedPPVar::PassRef(),
+                              CreateVarFromValue(iter.value()));
+        if (child_var.get().type == PP_VARTYPE_UNDEFINED ||
+            !dict_var->SetWithStringKey(iter.key(), child_var.get())) {
+          return PP_MakeUndefined();
+        }
+      }
+
+      return dict_var->GetPPVar();
+    }
+    case base::Value::TYPE_LIST: {
+      // TODO(yzshen): Add support once array var is supported.
+      return PP_MakeUndefined();
+    }
+  }
+  NOTREACHED();
+  return PP_MakeUndefined();
+}
+
+}  // namespace ppapi
+