Refactor the library tag handler to share code between standalone dart and the snapshot generator.

bin/process_script.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.
-
-// Handle dart scripts.
-
-#include <stdlib.h>
-#include <string.h>
-#include <stdio.h>
-
-#include "include/dart_api.h"
-
-#include "bin/builtin.h"
-#include "bin/file.h"
-#include "bin/globals.h"
-#include "bin/process_script.h"
-
-const char* GetCanonicalPath(const char* reference_dir,
-                             const char* filename) {
-  if (File::IsAbsolutePath(filename)) {
-    return strdup(filename);
-  }
-
-  char* path = strdup(reference_dir);
-  if  (path == NULL) {
-    return NULL;
-  }
-  char* path_sep = strrchr(path, File::PathSeparator()[0]);
-  if (path_sep == NULL) {
-    // No separator found: Reference is a file in local directory.
-    return strdup(filename);
-  }
-  *path_sep = '\0';
-  intptr_t len = snprintf(NULL, 0, "%s%s%s",
-                          path, File::PathSeparator(), filename);
-  char* absolute_filename = reinterpret_cast<char*>(malloc(len + 1));
-  ASSERT(absolute_filename != NULL);
-
-  snprintf(absolute_filename, len + 1, "%s%s%s",
-           path, File::PathSeparator(), filename);
-
-  free(path);
-  char* canonical_filename = File::GetCanonicalPath(absolute_filename);
-  if (canonical_filename == NULL) {
-    return absolute_filename;
-  }
-  free(absolute_filename);
-  return canonical_filename;
-}
-
-
-static Dart_Handle LibraryTagHandler(Dart_LibraryTag tag,
-                                     Dart_Handle library,
-                                     Dart_Handle url) {
-  if (!Dart_IsLibrary(library)) {
-    return Dart_Error("not a library");
-  }
-  if (!Dart_IsString8(url)) {
-    return Dart_Error("url is not a string");
-  }
-  const char* url_chars = NULL;
-  Dart_Handle result = Dart_StringToCString(url, &url_chars);
-  if (Dart_IsError(result)) {
-    return Dart_Error("accessing url characters failed");
-  }
-
-  static const char* kDartScheme = "dart:";
-  static const intptr_t kDartSchemeLen = strlen(kDartScheme);
-  // If the URL starts with "dart:" then it is not modified as it will be
-  // handled by the VM internally.
-  if (strncmp(url_chars, kDartScheme, kDartSchemeLen) == 0) {
-    if (tag == kCanonicalizeUrl) {
-      return url;
-    }
-    return Dart_Error("Do not know how to load '%s'", url_chars);
-  }
-  if (tag == kCanonicalizeUrl) {
-    // Create a canonical path based on the including library and current url.
-
-    // Get the url of the including library.
-    Dart_Handle library_url = Dart_LibraryUrl(library);
-    if (Dart_IsError(library_url)) {
-      return Dart_Error("accessing library url failed");
-    }
-    if (!Dart_IsString8(library_url)) {
-      return Dart_Error("library url is not a string");
-    }
-    const char* library_url_chars = NULL;
-    result = Dart_StringToCString(library_url, &library_url_chars);
-    if (Dart_IsError(result)) {
-      return Dart_Error("accessing library url characters failed");
-    }
-
-    // Calculate the canonical path.
-    const char* canon_url_chars = GetCanonicalPath(library_url_chars,
-                                                   url_chars);
-    Dart_Handle canon_url = Dart_NewString(canon_url_chars);
-    free(const_cast<char*>(canon_url_chars));
-
-    return canon_url;
-  }
-
-  // The tag is either an import or a source tag. Read the file based on the
-  // url chars.
-  Dart_Handle source = ReadStringFromFile(url_chars);
-  if (Dart_IsError(source)) {
-    return source;  // source contains the error string.
-  }
-  if (tag == kImportTag) {
-    Dart_Handle new_lib = Dart_LoadLibrary(url, source);
-    if (!Dart_IsError(new_lib)) {
-      Builtin_ImportLibrary(new_lib);
-    }
-    return new_lib;  // Return library object or an error string.
-  } else if (tag == kSourceTag) {
-    return Dart_LoadSource(library, url, source);
-  }
-  return Dart_Error("wrong tag");
-}
-
-
-Dart_Handle ReadStringFromFile(const char* filename) {
-  File* file = File::Open(filename, false);
-  if (file == NULL) {
-    const char* format = "Unable to open file: %s";
-    intptr_t len = snprintf(NULL, 0, format, filename);
-    // TODO(iposva): Allocate from the zone instead of leaking error string
-    // here. On the other hand the binary is about the exit anyway.
-    char* error_msg = reinterpret_cast<char*>(malloc(len + 1));
-    snprintf(error_msg, len + 1, format, filename);
-    return Dart_Error(error_msg);
-  }
-  intptr_t len = file->Length();
-  char* text_buffer = reinterpret_cast<char*>(malloc(len + 1));
-  if (text_buffer == NULL) {
-    delete file;
-    return Dart_Error("Unable to allocate buffer");
-  }
-  if (!file->ReadFully(text_buffer, len)) {
-    delete file;
-    return Dart_Error("Unable to fully read contents");
-  }
-  text_buffer[len] = '\0';
-  delete file;
-  Dart_Handle str = Dart_NewString(text_buffer);
-  free(text_buffer);
-  return str;
-}
-
-
-Dart_Handle LoadScript(const char* script_name) {
-  Dart_Handle source = ReadStringFromFile(script_name);
-  if (Dart_IsError(source)) {
-    return source;
-  }
-  Dart_Handle url = Dart_NewString(script_name);
-
-  return Dart_LoadScript(url, source, LibraryTagHandler);
-}