Add support for surrogates when serializing and deserializing for native ports

runtime/vm/dart_api_message.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/dart_api_message.h"
 #include "vm/object.h"
 #include "vm/snapshot_ids.h"
 #include "vm/symbols.h"
 #include "vm/unicode.h"
 
@@ skipping 371 matching lines @@
       ::free(latin1);
       return object;
     }
     case kTwoByteStringCid: {
       intptr_t len = ReadSmiValue();
       intptr_t hash = ReadSmiValue();
       USE(hash);
       uint16_t *utf16 =
           reinterpret_cast<uint16_t*>(::malloc(len * sizeof(uint16_t)));
       intptr_t utf8_len = 0;
+      // Read all the UTF-16 code units.
       for (intptr_t i = 0; i < len; i++) {
         utf16[i] = Read<uint16_t>();
-        // TODO(sgjesse): Check for surrogate pairs.
-        utf8_len += Utf8::Length(utf16[i]);
+      }
+      // Calculate the UTF-8 length.
+      Utf16::CodePointIterator it(utf16, len);
+      while (it.Next()) {
+        utf8_len += Utf8::Length(it.Current());
       }
       Dart_CObject* object = AllocateDartCObjectString(utf8_len);
       AddBackRef(object_id, object, kIsDeserialized);
       char* p = object->value.as_string;
-      for (intptr_t i = 0; i < len; i++) {
-        // TODO(sgjesse): Check for surrogate pairs.
-        p += Utf8::Encode(utf16[i], p);
+      it.Reset();
+      while (it.Next()) {
+        p += Utf8::Encode(it.Current(), p);
       }

[siva, 2012/11/28 22:02:24]

At this point here we could state that if malformed Dart strings are trying to
be passed out to the native world we could flag them as error. That way we can
say that only valid utf8 strings will be sent to the native world.

[Søren Gjesse, 2012/11/29 09:06:14]

Done.

       *p = '\0';
       ASSERT(p == (object->value.as_string + utf8_len));
       ::free(utf16);
       return object;
     }
     case kUint8ArrayCid: {
       intptr_t len = ReadSmiValue();
       Dart_CObject* object = AllocateDartCObjectUint8Array(len);
       AddBackRef(object_id, object, kIsDeserialized);
       if (len > 0) {
@@ skipping 386 matching lines @@
       // Write out the class and tags information.
       WriteIndexedObject(type == Utf8::kLatin1 ? kOneByteStringCid
                                                : kTwoByteStringCid);
       WriteIntptrValue(0);
       // Write string length, hash and content
       WriteSmi(len);
       WriteSmi(0);  // TODO(sgjesse): Hash - not written.
       if (type == Utf8::kLatin1) {
         uint8_t* latin1_str =
             reinterpret_cast<uint8_t*>(::malloc(len * sizeof(uint8_t)));
-        Utf8::DecodeToLatin1(utf8_str, utf8_len, latin1_str, len);
+        bool success = Utf8::DecodeToLatin1(utf8_str,
+                                            utf8_len,
+                                            latin1_str,
+                                            len);
+        ASSERT(success);
         for (intptr_t i = 0; i < len; i++) {
           Write<uint8_t>(latin1_str[i]);
         }
         ::free(latin1_str);
       } else {
         // TODO(sgjesse): Make sure surrogate pairs are handled.
         uint16_t* utf16_str =
             reinterpret_cast<uint16_t*>(::malloc(len * sizeof(uint16_t)));
-        Utf8::DecodeToUTF16(utf8_str, utf8_len, utf16_str, len);
+        bool success = Utf8::DecodeToUTF16(utf8_str, utf8_len, utf16_str, len);
+        ASSERT(success);
         for (intptr_t i = 0; i < len; i++) {
           Write<uint16_t>(utf16_str[i]);
         }
         ::free(utf16_str);
       }
       break;
     }
     case Dart_CObject::kUint8Array: {
       // Write out the serialization header value for this object.
       WriteInlinedHeader(object);
@@ skipping 52 matching lines @@
     if (!success) {
       UnmarkAllCObjects(object);
       return false;
     }
   }
   UnmarkAllCObjects(object);
   return true;
 }
 
 }  // namespace dart