ppapi/shared_impl/var_value_conversions.cc

   1 // Copyright (c) 2013 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 #include "ppapi/shared_impl/var_value_conversions.h"
   6
   7 #include <limits>
   8 #include <set>
   9 #include <stack>
  10
  11 #include "base/logging.h"
  12 #include "base/memory/ref_counted.h"
  13 #include "base/memory/scoped_ptr.h"
  14 #include "base/stl_util.h"
  15 #include "base/values.h"
  16 #include "ppapi/c/pp_bool.h"
  17 #include "ppapi/c/pp_stdint.h"
  18 #include "ppapi/shared_impl/array_var.h"
  19 #include "ppapi/shared_impl/dictionary_var.h"
  20 #include "ppapi/shared_impl/ppapi_globals.h"
  21 #include "ppapi/shared_impl/scoped_pp_var.h"
  22 #include "ppapi/shared_impl/var.h"
  23 #include "ppapi/shared_impl/var_tracker.h"
  24
  25 namespace ppapi {
  26
  27 namespace {
  28
  29 // In CreateValueFromVar(), a stack is used to keep track of conversion progress
  30 // of array and dictionary vars. VarNode represents elements of that stack.
  31 struct VarNode {
  32   VarNode(const PP_Var& in_var, base::Value* in_value)
  33       : var(in_var),
  34         value(in_value),
  35         sentinel(false) {
  36   }
  37
  38   // This object doesn't hold a reference to it.
  39   PP_Var var;
  40   // It is not owned by this object.
  41   base::Value* value;
  42   // When this is set to true for a node in the stack, it means that we have
  43   // finished processing the node itself. However, we keep it in the stack as
  44   // a sentinel. When it becomes the top element of the stack again, we know
  45   // that we have processed all the descendants of this node.
  46   bool sentinel;
  47 };
  48
  49 // In CreateVarFromValue(), a stack is used to keep track of conversion progress
  50 // of list and dictionary values. ValueNode represents elements of that stack.
  51 struct ValueNode {
  52   ValueNode(const PP_Var& in_var, const base::Value* in_value)
  53       : var(in_var),
  54         value(in_value) {
  55   }
  56
  57   // This object doesn't hold a reference to it.
  58   PP_Var var;
  59   // It is not owned by this object.
  60   const base::Value* value;
  61 };
  62
  63 // Helper function for CreateValueFromVar(). It only looks at |var| but not its
  64 // descendants. The conversion result is stored in |value|. If |var| is array or
  65 // dictionary, a new node is pushed onto |state|.
  66 //
  67 // Returns false on failure.
  68 bool CreateValueFromVarHelper(const std::set<int64_t>& parent_ids,
  69                               const PP_Var& var,
  70                               scoped_ptr<base::Value>* value,
  71                               std::stack<VarNode>* state) {
  72   switch (var.type) {
  73     case PP_VARTYPE_UNDEFINED:
  74     case PP_VARTYPE_NULL: {
  75       value->reset(base::Value::CreateNullValue());
  76       return true;
  77     }
  78     case PP_VARTYPE_BOOL: {
  79       value->reset(new base::FundamentalValue(PP_ToBool(var.value.as_bool)));
  80       return true;
  81     }
  82     case PP_VARTYPE_INT32: {
  83       value->reset(new base::FundamentalValue(var.value.as_int));
  84       return true;
  85     }
  86     case PP_VARTYPE_DOUBLE: {
  87       value->reset(new base::FundamentalValue(var.value.as_double));
  88       return true;
  89     }
  90     case PP_VARTYPE_STRING: {
  91       StringVar* string_var = StringVar::FromPPVar(var);
  92       if (!string_var)
  93         return false;
  94
  95       value->reset(new base::StringValue(string_var->value()));
  96       return true;
  97     }
  98     case PP_VARTYPE_OBJECT: {
  99       return false;
 100     }
 101     case PP_VARTYPE_ARRAY: {
 102       if (ContainsKey(parent_ids, var.value.as_id)) {
 103         // A circular reference is found.
 104         return false;
 105       }
 106
 107       value->reset(new base::ListValue());
 108       state->push(VarNode(var, value->get()));
 109       return true;
 110     }
 111     case PP_VARTYPE_DICTIONARY: {
 112       if (ContainsKey(parent_ids, var.value.as_id)) {
 113         // A circular reference is found.
 114         return false;
 115       }
 116
 117       value->reset(new base::DictionaryValue());
 118       state->push(VarNode(var, value->get()));
 119       return true;
 120     }
 121     case PP_VARTYPE_ARRAY_BUFFER: {
 122       ArrayBufferVar* array_buffer = ArrayBufferVar::FromPPVar(var);
 123       if (!array_buffer)
 124         return false;
 125
 126       base::BinaryValue* binary_value =
 127           base::BinaryValue::CreateWithCopiedBuffer(
 128               static_cast<const char*>(array_buffer->Map()),
 129               array_buffer->ByteLength());
 130       array_buffer->Unmap();
 131       value->reset(binary_value);
 132       return true;
 133     }
 134     case PP_VARTYPE_RESOURCE: {
 135       return false;
 136     }
 137   }
 138   NOTREACHED();
 139   return false;
 140 }
 141
 142 // Helper function for CreateVarFromValue(). It only looks at |value| but not
 143 // its descendants. The conversion result is stored in |var|. If |value| is list
 144 // or dictionary, a new node is pushed onto |state|.
 145 //
 146 // Returns false on failure.
 147 bool CreateVarFromValueHelper(const base::Value& value,
 148                               ScopedPPVar* var,
 149                               std::stack<ValueNode>* state) {
 150   switch (value.GetType()) {
 151     case base::Value::TYPE_NULL: {
 152       *var = PP_MakeNull();
 153       return true;
 154     }
 155     case base::Value::TYPE_BOOLEAN: {
 156       bool result = false;
 157       if (value.GetAsBoolean(&result)) {
 158         *var = PP_MakeBool(PP_FromBool(result));
 159         return true;
 160       }
 161       return false;
 162     }
 163     case base::Value::TYPE_INTEGER: {
 164       int result = 0;
 165       if (value.GetAsInteger(&result)) {
 166         *var = PP_MakeInt32(result);
 167         return true;
 168       }
 169       return false;
 170     }
 171     case base::Value::TYPE_DOUBLE: {
 172       double result = 0;
 173       if (value.GetAsDouble(&result)) {
 174         *var = PP_MakeDouble(result);
 175         return true;
 176       }
 177       return false;
 178     }
 179     case base::Value::TYPE_STRING: {
 180       std::string result;
 181       if (value.GetAsString(&result)) {
 182         *var = ScopedPPVar(ScopedPPVar::PassRef(),
 183                            StringVar::StringToPPVar(result));
 184         return true;
 185       }
 186       return false;
 187     }
 188     case base::Value::TYPE_BINARY: {
 189       const base::BinaryValue& binary_value =
 190           static_cast<const base::BinaryValue&>(value);
 191
 192       size_t size = binary_value.GetSize();
 193       if (size > std::numeric_limits<uint32>::max())
 194         return false;
 195
 196       ScopedPPVar temp(
 197           ScopedPPVar::PassRef(),
 198           PpapiGlobals::Get()->GetVarTracker()->MakeArrayBufferPPVar(
 199               static_cast<uint32>(size), binary_value.GetBuffer()));
 200       if (temp.get().type == PP_VARTYPE_ARRAY_BUFFER) {
 201         *var = temp;
 202         return true;
 203       }
 204       return false;
 205     }
 206     case base::Value::TYPE_DICTIONARY: {
 207       scoped_refptr<DictionaryVar> dict_var(new DictionaryVar());
 208       *var = ScopedPPVar(ScopedPPVar::PassRef(), dict_var->GetPPVar());
 209       state->push(ValueNode(var->get(), &value));
 210       return true;
 211     }
 212     case base::Value::TYPE_LIST: {
 213       scoped_refptr<ArrayVar> array_var(new ArrayVar());
 214       *var = ScopedPPVar(ScopedPPVar::PassRef(), array_var->GetPPVar());
 215       state->push(ValueNode(var->get(), &value));
 216       return true;
 217     }
 218   }
 219   NOTREACHED();
 220   return false;
 221 }
 222
 223 }  // namespace
 224
 225 base::Value* CreateValueFromVar(const PP_Var& var) {
 226   // Used to detect circular references.
 227   std::set<int64_t> parent_ids;
 228   std::stack<VarNode> state;
 229   scoped_ptr<base::Value> root_value;
 230
 231   if (!CreateValueFromVarHelper(parent_ids, var, &root_value, &state))
 232     return NULL;
 233
 234   while (!state.empty()) {
 235     VarNode& top = state.top();
 236     if (top.sentinel) {
 237       parent_ids.erase(top.var.value.as_id);
 238       state.pop();
 239     } else if (top.var.type == PP_VARTYPE_DICTIONARY) {
 240       parent_ids.insert(top.var.value.as_id);
 241       top.sentinel = true;
 242
 243       DictionaryVar* dict_var = DictionaryVar::FromPPVar(top.var);
 244       if (!dict_var)
 245         return NULL;
 246
 247       DCHECK(top.value->GetType() == base::Value::TYPE_DICTIONARY);
 248       base::DictionaryValue* dict_value =
 249           static_cast<base::DictionaryValue*>(top.value);
 250
 251       for (DictionaryVar::KeyValueMap::const_iterator iter =
 252                dict_var->key_value_map().begin();
 253            iter != dict_var->key_value_map().end();
 254            ++iter) {
 255         // Skip the key-value pair if the value is undefined or null.
 256         if (iter->second.get().type == PP_VARTYPE_UNDEFINED ||
 257             iter->second.get().type == PP_VARTYPE_NULL) {
 258           continue;
 259         }
 260
 261         scoped_ptr<base::Value> child_value;
 262         if (!CreateValueFromVarHelper(parent_ids, iter->second.get(),
 263                                       &child_value, &state)) {
 264           return NULL;
 265         }
 266
 267         dict_value->SetWithoutPathExpansion(iter->first, child_value.release());
 268       }
 269     } else if (top.var.type == PP_VARTYPE_ARRAY) {
 270       parent_ids.insert(top.var.value.as_id);
 271       top.sentinel = true;
 272
 273       ArrayVar* array_var = ArrayVar::FromPPVar(top.var);
 274       if (!array_var)
 275         return NULL;
 276
 277       DCHECK(top.value->GetType() == base::Value::TYPE_LIST);
 278       base::ListValue* list_value = static_cast<base::ListValue*>(top.value);
 279
 280       for (ArrayVar::ElementVector::const_iterator iter =
 281                array_var->elements().begin();
 282            iter != array_var->elements().end();
 283            ++iter) {
 284         scoped_ptr<base::Value> child_value;
 285         if (!CreateValueFromVarHelper(parent_ids, iter->get(), &child_value,
 286                                       &state)) {
 287           return NULL;
 288         }
 289
 290         list_value->Append(child_value.release());
 291       }
 292     } else {
 293       NOTREACHED();
 294       return NULL;
 295     }
 296   }
 297   DCHECK(parent_ids.empty());
 298   return root_value.release();
 299 }
 300
 301 PP_Var CreateVarFromValue(const base::Value& value) {
 302   std::stack<ValueNode> state;
 303   ScopedPPVar root_var;
 304
 305   if (!CreateVarFromValueHelper(value, &root_var, &state))
 306     return PP_MakeUndefined();
 307
 308   while (!state.empty()) {
 309     ValueNode top = state.top();
 310     state.pop();
 311
 312     if (top.value->GetType() == base::Value::TYPE_DICTIONARY) {
 313       const base::DictionaryValue* dict_value =
 314           static_cast<const base::DictionaryValue*>(top.value);
 315       DictionaryVar* dict_var = DictionaryVar::FromPPVar(top.var);
 316       DCHECK(dict_var);
 317       for (base::DictionaryValue::Iterator iter(*dict_value);
 318            !iter.IsAtEnd();
 319            iter.Advance()) {
 320         ScopedPPVar child_var;
 321         if (!CreateVarFromValueHelper(iter.value(), &child_var, &state) ||
 322             !dict_var->SetWithStringKey(iter.key(), child_var.get())) {
 323           return PP_MakeUndefined();
 324         }
 325       }
 326     } else if (top.value->GetType() == base::Value::TYPE_LIST) {
 327       const base::ListValue* list_value =
 328           static_cast<const base::ListValue*>(top.value);
 329       ArrayVar* array_var = ArrayVar::FromPPVar(top.var);
 330       DCHECK(array_var);
 331       for (base::ListValue::const_iterator iter = list_value->begin();
 332            iter != list_value->end();
 333            ++iter) {
 334         ScopedPPVar child_var;
 335         if (!CreateVarFromValueHelper(**iter, &child_var, &state))
 336           return PP_MakeUndefined();
 337
 338         array_var->elements().push_back(child_var);
 339       }
 340     } else {
 341       NOTREACHED();
 342       return PP_MakeUndefined();
 343     }
 344   }
 345
 346   return root_var.Release();
 347 }
 348
 349 base::ListValue* CreateListValueFromVarVector(
 350     const std::vector<PP_Var>& vars) {
 351   scoped_ptr<base::ListValue> list_value(new base::ListValue());
 352
 353   for (std::vector<PP_Var>::const_iterator iter = vars.begin();
 354        iter != vars.end();
 355        ++iter) {
 356     base::Value* value = CreateValueFromVar(*iter);
 357     if (!value)
 358       return NULL;
 359     list_value->Append(value);
 360   }
 361   return list_value.release();
 362 }
 363
 364 bool CreateVarVectorFromListValue(const base::ListValue& list_value,
 365                                   std::vector<PP_Var>* vars) {
 366   if (!vars)
 367     return false;
 368
 369   std::vector<ScopedPPVar> result;
 370   result.reserve(list_value.GetSize());
 371   for (base::ListValue::const_iterator iter = list_value.begin();
 372        iter != list_value.end();
 373        ++iter) {
 374     ScopedPPVar child_var(ScopedPPVar::PassRef(),
 375                           CreateVarFromValue(**iter));
 376     if (child_var.get().type == PP_VARTYPE_UNDEFINED)
 377       return false;
 378
 379     result.push_back(child_var);
 380   }
 381
 382   vars->clear();
 383   vars->reserve(result.size());
 384   for (std::vector<ScopedPPVar>::iterator iter = result.begin();
 385        iter != result.end();
 386        ++iter) {
 387     vars->push_back(iter->Release());
 388   }
 389
 390   return true;
 391 }
 392
 393 }  // namespace ppapi
 394