Implement external strings.

runtime/vm/dart_api_impl.cc

Index: runtime/vm/dart_api_impl.cc
diff --git a/runtime/vm/dart_api_impl.cc b/runtime/vm/dart_api_impl.cc
index 3c2932efc6c7995b21660180e8142758adb1fb3e..07d2494ab354c7ebb38a39f4424a1d27cdcef4c3 100644
--- a/runtime/vm/dart_api_impl.cc
+++ b/runtime/vm/dart_api_impl.cc
@@ -723,17 +723,55 @@ DART_EXPORT Dart_Handle Dart_NewString32(const uint32_t* codepoints,
                                          intptr_t length) {
   Zone zone;  // Setup a VM zone as we are creating some handles.
   HandleScope scope;  // Setup a VM handle scope.
-  UNIMPLEMENTED();
   const String& obj = String::Handle(String::New(codepoints, length));
   return Api::NewLocalHandle(obj);
 }
 
 
+DART_EXPORT Dart_Handle Dart_NewExternalString8(
+    uint8_t* codepoints,
+    intptr_t length,
+    void* peer,
+    Dart_ExternalString8Finalizer finalizer) {
+  Zone zone;  // Setup a VM zone as we are creating some handles.
+  HandleScope scope;  // Setup a VM handle scope.
+  const String& obj =
+      String::Handle(String::NewExternal(codepoints, length, peer));
+  return Api::NewLocalHandle(obj);
+}
+
+
+DART_EXPORT Dart_Handle Dart_NewExternalString16(
+    uint16_t* codepoints,
+    intptr_t length,
+    void* peer,
+    Dart_ExternalString16Finalizer finalizer) {
+  Zone zone;  // Setup a VM zone as we are creating some handles.
+  HandleScope scope;  // Setup a VM handle scope.
+  const String& obj =
+      String::Handle(String::NewExternal(codepoints, length, peer));
+  return Api::NewLocalHandle(obj);
+}
+
+
+DART_EXPORT Dart_Handle Dart_NewExternalString32(
+    uint32_t* codepoints,
+    intptr_t length,
+    void* peer,
+    Dart_ExternalString32Finalizer finalizer) {
+  Zone zone;  // Setup a VM zone as we are creating some handles.
+  HandleScope scope;  // Setup a VM handle scope.
+  const String& obj =
+      String::Handle(String::NewExternal(codepoints, length, peer));
+  return Api::NewLocalHandle(obj);
+}
+
+
 DART_EXPORT bool Dart_IsString8(Dart_Handle object) {
   Zone zone;  // Setup a VM zone as we are creating some handles.
   HandleScope scope;  // Setup a VM handle scope.
   const Object& obj = Object::Handle(Api::UnwrapHandle(object));
-  return obj.IsOneByteString();
+  return obj.IsOneByteString() || obj.IsExternalOneByteString();
 }
 
 
@@ -741,7 +779,8 @@ DART_EXPORT bool Dart_IsString16(Dart_Handle object) {
   Zone zone;  // Setup a VM zone as we are creating some handles.
   HandleScope scope;  // Setup a VM handle scope.
   const Object& obj = Object::Handle(Api::UnwrapHandle(object));
-  return obj.IsOneByteString() || obj.IsTwoByteString();
+  return (obj.IsOneByteString() || obj.IsExternalOneByteString() ||
+          obj.IsTwoByteString() || obj.IsExternalOneByteString());
 }
 
 
@@ -751,15 +790,17 @@ DART_EXPORT Dart_Result Dart_StringGet8(Dart_Handle str,
   Zone zone;  // Setup a VM zone as we are creating some handles.
   HandleScope scope;  // Setup a VM handle scope.
   const Object& obj = Object::Handle(Api::UnwrapHandle(str));
-  if (obj.IsOneByteString()) {
-    OneByteString& string_obj = OneByteString::Handle();
+  if (obj.IsString()) {
+    String& string_obj = String::Handle();
     string_obj ^= obj.raw();
-    intptr_t str_len = string_obj.Length();
-    intptr_t copy_len = (str_len > length) ? length : str_len;
-    for (intptr_t i = 0; i < copy_len; i++) {
-      codepoints[i] = static_cast<uint8_t>(string_obj.CharAt(i));
+    if (string_obj.CharSize() == String::kOneByteChar) {
+      intptr_t str_len = string_obj.Length();
+      intptr_t copy_len = (str_len > length) ? length : str_len;
+      for (intptr_t i = 0; i < copy_len; i++) {
+        codepoints[i] = static_cast<uint8_t>(string_obj.CharAt(i));
+      }
+      RETURN_CINT(copy_len);
     }
-    RETURN_CINT(copy_len);
   }
   RETURN_FAILURE(obj.IsString() ? "Object is not a String8" :
                                   "Object is not a String");
@@ -772,15 +813,17 @@ DART_EXPORT Dart_Result Dart_StringGet16(Dart_Handle str,
   Zone zone;  // Setup a VM zone as we are creating some handles.
   HandleScope scope;  // Setup a VM handle scope.
   const Object& obj = Object::Handle(Api::UnwrapHandle(str));
-  if (obj.IsOneByteString() || obj.IsTwoByteString()) {
+  if (obj.IsString()) {
     String& string_obj = String::Handle();
     string_obj ^= obj.raw();
-    intptr_t str_len = string_obj.Length();
-    intptr_t copy_len = (str_len > length) ? length : str_len;
-    for (intptr_t i = 0; i < copy_len; i++) {
-      codepoints[i] = static_cast<uint16_t>(string_obj.CharAt(i));
+    if (string_obj.CharSize() <= String::kTwoByteChar) {
+      intptr_t str_len = string_obj.Length();
+      intptr_t copy_len = (str_len > length) ? length : str_len;
+      for (intptr_t i = 0; i < copy_len; i++) {
+        codepoints[i] = static_cast<uint16_t>(string_obj.CharAt(i));
+      }
+      RETURN_CINT(copy_len);
     }
-    RETURN_CINT(copy_len);
   }
   RETURN_FAILURE(obj.IsString() ? "Object is not a String16" :
                                   "Object is not a String");
@@ -796,12 +839,14 @@ DART_EXPORT Dart_Result Dart_StringGet32(Dart_Handle str,
   if (obj.IsString()) {
     String& string_obj = String::Handle();
     string_obj ^= obj.raw();
-    intptr_t str_len = string_obj.Length();
-    intptr_t copy_len = (str_len > length) ? length : str_len;
-    for (intptr_t i = 0; i < copy_len; i++) {
-      codepoints[i] = static_cast<uint32_t>(string_obj.CharAt(i));
+    if (string_obj.CharSize() <= String::kFourByteChar) {
+      intptr_t str_len = string_obj.Length();
+      intptr_t copy_len = (str_len > length) ? length : str_len;
+      for (intptr_t i = 0; i < copy_len; i++) {
+        codepoints[i] = static_cast<uint32_t>(string_obj.CharAt(i));
+      }
+      RETURN_CINT(copy_len);
     }
-    RETURN_CINT(copy_len);
   }
   RETURN_FAILURE("Object is not a String");
 }
@@ -826,6 +871,31 @@ DART_EXPORT Dart_Result Dart_StringToCString(Dart_Handle object) {
 }
 
 
+DART_EXPORT Dart_Result Dart_ExternalStringPeer(Dart_Handle object,
+                                                void** peer) {
+  const Object& obj = Object::Handle(Api::UnwrapHandle(object));
+  if (obj.IsExternalOneByteString()) {
+    ExternalOneByteString& str = ExternalOneByteString::Handle();
+    str ^= obj.raw();
+    *peer = str.Peer();
+    RETURN_CBOOLEAN(true);
+  }
+  if (obj.IsExternalTwoByteString()) {
+    ExternalTwoByteString& str = ExternalTwoByteString::Handle();
+    str ^= obj.raw();
+    *peer = str.Peer();
+    RETURN_CBOOLEAN(true);
+  }
+  if (obj.IsExternalFourByteString()) {
+    ExternalFourByteString& str = ExternalFourByteString::Handle();
+    str ^= obj.raw();
+    *peer = str.Peer();
+    RETURN_CBOOLEAN(true);
+  }
+  RETURN_FAILURE("Object is not an external String");
+}
+
+
 DART_EXPORT bool Dart_IsArray(Dart_Handle object) {
   Zone zone;  // Setup a VM zone as we are creating some handles.
   HandleScope scope;  // Setup a VM handle scope.