- Refactor the isolate callback mechanism to also include creation of the

bin/gen_snapshot.cc

 // Copyright (c) 2011, 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.
 
 // Generate a snapshot file after loading all the scripts specified on the
 // command line.
 
 #include <stdlib.h>
 #include <string.h>
 #include <stdio.h>
 
 #include "include/dart_api.h"
 
 #include "bin/builtin.h"
 #include "bin/dartutils.h"
 #include "bin/file.h"
 #include "bin/globals.h"
 
 // Global state that indicates whether a snapshot is to be created and
 // if so which file to write the snapshot into.
 static const char* snapshot_filename = NULL;
 
+
+// Global state which containts a pointer to the script name for which
+// a snapshot needs to be created (NULL would result in the creation
+// of a generic snapshot that contains only the corelibs).
+static char* app_script_name = NULL;
+
+
 // Global state that captures the URL mappings specified on the command line.
 static CommandLineOptions* url_mapping = NULL;
 
 static bool IsValidFlag(const char* name,
                         const char* prefix,
                         intptr_t prefix_length) {
   intptr_t name_length = strlen(name);
   return ((name_length > prefix_length) &&
           (strncmp(name, prefix, prefix_length) == 0));
 }
@@ skipping 132 matching lines @@
     if (tag == kCanonicalizeUrl) {
       return url;
     }
     return Dart_Error("unsupported url encountered %s", url_string);
   }
   return Dart_Error("unexpected tag encountered %d", tag);
 }
 
 
 static Dart_Handle LoadGenericSnapshotCreationScript() {
-  Dart_Handle source = Builtin_Source();
+  Dart_Handle source = Builtin::Source();
   if (Dart_IsError(source)) {
     return source;  // source contains the error string.
   }
   Dart_Handle url = Dart_NewString(DartUtils::kBuiltinLibURL);
   Dart_Handle lib = Dart_LoadScript(url, source, BuiltinLibraryTagHandler);
   if (!Dart_IsError(lib)) {
-    Builtin_SetupLibrary(lib);
+    Builtin::SetupLibrary(lib);
   }
   return lib;
 }
 
 
-static void* SnapshotCreateCallback(void* data) {
-  const char* script_name = reinterpret_cast<const char*>(data);
-  Dart_Handle result;
-  Dart_Handle library;
-  Dart_EnterScope();
-
-  ASSERT(snapshot_filename != NULL);
-
-  // Load up the script before a snapshot is created.
-  if (script_name != NULL) {
-    // Load the specified script.
-    library = LoadSnapshotCreationScript(script_name);
-  } else {
-    // This is a generic dart snapshot which needs builtin library setup.
-    library = LoadGenericSnapshotCreationScript();
-  }
-  if (Dart_IsError(library)) {
-    const char* err_msg = Dart_GetError(library);
-    fprintf(stderr, "Errors encountered while loading script: %s\n", err_msg);
-    Dart_ExitScope();
-    exit(255);
-  }
-  ASSERT(Dart_IsLibrary(library));
-  uint8_t* buffer = NULL;
-  intptr_t size = 0;
-  // First create the snapshot.
-  result = Dart_CreateSnapshot(&buffer, &size);
-  if (Dart_IsError(result)) {
-    const char* err_msg = Dart_GetError(result);
-    fprintf(stderr, "Error while creating snapshot: %s\n", err_msg);
-    Dart_ExitScope();
-    exit(255);
-  }
-  // Now write the snapshot out to specified file and exit.
-  WriteSnapshotFile(buffer, size);
-  Dart_ExitScope();
-  return data;
+static bool CreateIsolateAndSetup(Dart_IsolateError error) {
+  snprintf(const_cast<char*>(error.buffer), error.length,
+           "Isolates are not expected to be created from dart"
+           " while generating snapshots");

[turnidge, 2011/11/23 18:05:12]

Should we put an UNREACHABLE here?

[siva, 2011/11/23 18:24:40]

Done.

+  return false;
 }
 
 
 static void PrintUsage() {
   fprintf(stderr,
           "dart [<vm-flags>] "
           "[<dart-script-file>]\n");
 }
 
 
 int main(int argc, char** argv) {
   CommandLineOptions vm_options(argc);
-  char* script_name;
 
   // Initialize the URL mapping array.
   CommandLineOptions url_mapping_array(argc);
   url_mapping = &url_mapping_array;
 
   // Parse command line arguments.
   if (ParseArguments(argc,
                      argv,
                      &vm_options,
-                     &script_name) < 0) {
+                     &app_script_name) < 0) {
     PrintUsage();
     return 255;
   }
 
   if (snapshot_filename == NULL) {
     fprintf(stderr, "No snapshot output file specified\n");
     return 255;
   }
 
   // Initialize the Dart VM (TODO(asiva) - remove const_cast once
   // dart API is fixed to take a const char** in Dart_Initialize).
+  // Note: We don't expect isolates to be created from dart code during
+  // snapshot generation.

[turnidge, 2011/11/23 18:05:12]

Instead of having this comment you could consider changing the name of the
callback from "CreateIsolateAndSetup" to something that documents this like
"DoNotCreateIsolate".

[siva, 2011/11/23 18:24:40]

I renamed the callback to "DoNotCreateIsolate" but left the comment.
I could pass a NULL and check for that during invocation, do you think that
would be more readable?

On 2011/11/23 18:05:12, turnidge wrote:

[turnidge, 2011/11/23 19:03:33]

About the NULL, I don't really have a strong opinion.  It seems like it only
comes up in this one case.

[siva, 2011/11/23 22:37:27]

I have added a check in Dart_Initialize to avoid NULL being passed in as the
callback argument.

On 2011/11/23 19:03:33, turnidge wrote:

   Dart_Initialize(vm_options.count(),
                   vm_options.arguments(),
-                  SnapshotCreateCallback);
+                  CreateIsolateAndSetup);
 
-  // Create an isolate. As a side effect, SnapshotCreateCallback
-  // gets called, which loads the script (if one is specified), its libraries
-  // and writes out a snapshot.
-  Dart_Isolate isolate = Dart_CreateIsolate(NULL, script_name);
+  Dart_Isolate isolate = Dart_CreateIsolate(NULL);
   if (isolate == NULL) {
-    return 255;
+    fprintf(stderr, "Creation/Bootstrap of Isolate failed");
+    exit(255);
   }
 
+  Dart_Handle result;
+  Dart_Handle library;
+  Dart_EnterScope();
+
+  ASSERT(snapshot_filename != NULL);
+  // Load up the script before a snapshot is created.
+  if (app_script_name != NULL) {
+    // Load the specified script.
+    library = LoadSnapshotCreationScript(app_script_name);
+  } else {
+    // This is a generic dart snapshot which needs builtin library setup.
+    library = LoadGenericSnapshotCreationScript();
+  }
+  if (Dart_IsError(library)) {
+    const char* err_msg = Dart_GetError(library);
+    fprintf(stderr, "Errors encountered while loading script: %s\n", err_msg);
+    Dart_ExitScope();
+    Dart_ShutdownIsolate();
+    exit(255);
+  }
+  ASSERT(Dart_IsLibrary(library));
+  uint8_t* buffer = NULL;
+  intptr_t size = 0;
+  // First create the snapshot.
+  result = Dart_CreateSnapshot(&buffer, &size);
+  if (Dart_IsError(result)) {
+    const char* err_msg = Dart_GetError(result);
+    fprintf(stderr, "Error while creating snapshot: %s\n", err_msg);
+    Dart_ExitScope();
+    Dart_ShutdownIsolate();
+    exit(255);
+  }
+  // Now write the snapshot out to specified file and exit.
+  WriteSnapshotFile(buffer, size);
+  Dart_ExitScope();
+
   // Shutdown the isolate.
   Dart_ShutdownIsolate();
   return 0;
 }