Add script streaming API

test/cctest/test-api.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 22982 matching lines @@
   desc = x->GetOwnPropertyDescriptor(v8_str("p1"));
   Local<Function> set =
     Local<Function>::Cast(Local<Object>::Cast(desc)->Get(v8_str("set")));
   Local<Function> get =
     Local<Function>::Cast(Local<Object>::Cast(desc)->Get(v8_str("get")));
   CHECK_EQ(v8_num(13), get->Call(x, 0, NULL));
   Handle<Value> args[] = { v8_num(14) };
   set->Call(x, 1, args);
   CHECK_EQ(v8_num(14), get->Call(x, 0, NULL));
 }
+
+class TestSourceStream : public v8::ScriptCompiler::ExternalSourceStream {
+ public:
+  explicit TestSourceStream(const char** chunks) : chunks_(chunks), index_(0) {
+    SetEncoding(v8::ScriptCompiler::ExternalSourceStream::ONE_BYTE);
+  }
+
+  virtual unsigned GetMoreData(const char** src) {
+    // Unlike in real use cases, this function will never block.
+    if (chunks_[index_] == NULL) {
+      return 0;
+    }
+    // Copy the data, since the caller takes ownership of it.
+    unsigned len = strlen(chunks_[index_]);

[Sven Panne, 2014/09/01 09:07:46]

size_t

[marja, 2014/09/01 11:58:17]

Done.

+    // snprintf will NULL-terminate, so reserve space for the NULL too. However,

[Sven Panne, 2014/09/01 09:07:46]

Nit: It zero-terminates, not NULL-terminates. :-) And even that is not
guaranteed. And some VisualStudio versions don't have it.

[marja, 2014/09/01 11:58:17]

Done.

+    // the caller is not interested in the NULL; we will return the real length
+    // below.
+    char* copy = new char[len + 1];
+    snprintf(copy, len + 1, "%s", chunks_[index_]);

[Sven Panne, 2014/09/01 09:07:46]

Wouldn't memcpy simplify things here and below?

[marja, 2014/09/01 11:58:17]

Yes, but presubmit whines about it :(

[jochen (gone - plz use gerrit), 2014/09/01 13:16:32]

why not strncpy?

[marja, 2014/09/01 13:23:25]

Argh, this discussion was confused.

So I originally had *strcpy* (not memcpy), but the whine was:

/media/ssdvol/v8-bleeding2/test/cctest/test-api.cc:23021:  Almost always,
snprintf is better than strcpy  [runtime/printf] [4]

(Curiously, it didn't suggest strncpy, so I thought snprintf is the way.)

However, memcpy is the right function here, since I don't want to mess with
0-termination.

+    *src = copy;
+    ++index_;
+    return len;
+  }
+
+  // Helper for constructing a string from chunks (the compilation needs it
+  // too).
+  static char* FullSourceString(const char** chunks) {
+    size_t total_len = 0;
+    for (size_t i = 0; chunks[i] != NULL; ++i) {
+      total_len += strlen(chunks[i]);
+    }
+    char* full_string = new char[total_len + 1];
+    size_t offset = 0;
+    for (size_t i = 0; chunks[i] != NULL; ++i) {
+      size_t len = strlen(chunks[i]);
+      snprintf(full_string + offset, len + 1, "%s", chunks[i]);
+      offset += len;
+    }
+    return full_string;
+  }
+
+ private:
+  const char** chunks_;
+  unsigned index_;
+};
+
+
+TEST(StreamingSimpleScript) {
+  LocalContext env;
+  v8::Isolate* isolate = env->GetIsolate();
+  v8::HandleScope scope(isolate);
+
+  // This script is unrealistically small, since no one chunk is enough to fill
+  // the backing buffer of Scanner, let alone overflow it. Other tests will
+  // cover those cases.
+  const char* chunks[] = {"function foo() { ret", "urn 3; } f", "oo(); ", NULL};
+  v8::ScriptCompiler::StreamedSource source(new TestSourceStream(chunks));
+  v8::ScriptCompiler::ScriptStreamingTask* task =
+      v8::ScriptCompiler::StartStreamingScript(isolate, &source);
+
+  // TestSourceStream::GetMoreData won't block, so it's okay to just run the
+  // task here in the main thread.
+  task->Run();
+  delete task;
+
+  v8::ScriptOrigin origin(v8_str("http://foo.com"));
+  char* full_source = TestSourceStream::FullSourceString(chunks);
+  v8::Handle<Script> script = v8::ScriptCompiler::Compile(
+      isolate, &source, v8_str(full_source), origin);
+  CHECK(!script.IsEmpty());
+  v8::Handle<Value> result(script->Run());
+  CHECK_EQ(3, result->Int32Value());
+  delete[] full_source;
+}