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

bin/dartutils.cc

Index: bin/dartutils.cc
===================================================================
--- bin/dartutils.cc	(revision 1664)
+++ bin/dartutils.cc	(working copy)
@@ -4,6 +4,10 @@
 
 #include "bin/dartutils.h"
 
+#include "bin/file.h"
+#include "bin/globals.h"
+
+const char* DartUtils::kDartScheme = "dart:";
 const char* DartUtils::kBuiltinLibURL = "dart:builtin";
 const char* DartUtils::kCoreLibURL = "dart:core";
 const char* DartUtils::kCoreImplLibURL = "dart:coreimpl";
@@ -11,6 +15,25 @@
 const char* DartUtils::kIdFieldName = "_id";
 
 
+static const char* MapLibraryUrl(CommandLineOptions* url_mapping,
+                                 const char* url_string) {
+  ASSERT(url_mapping != NULL);
+  // We need to check if the passed in url is found in the url_mapping array,
+  // in that case use the mapped entry.
+  int len = strlen(url_string);
+  for (int idx = 0; idx < url_mapping->count(); idx++) {
+    const char* url_name = url_mapping->GetArgument(idx);
+    if (!strncmp(url_string, url_name, len) && (url_name[len] == ',')) {
+      const char* url_mapped_name = url_name + len + 1;
+      if (strlen(url_mapped_name) != 0) {
+        return url_mapped_name;  // Found a mapping for this URL.
+      }
+    }
+  }
+  return NULL;  // Did not find a mapping for this URL.
+}
+
+
 int64_t DartUtils::GetIntegerValue(Dart_Handle value_obj) {
   ASSERT(Dart_IsInteger(value_obj));
   int64_t value = 0;
@@ -64,3 +87,136 @@
                                              Dart_NewString(val));
   ASSERT(!Dart_IsError(result));
 }
+
+
+bool DartUtils::IsDartSchemeURL(const char* url_name) {
+  static const intptr_t kDartSchemeLen = strlen(kDartScheme);
+  // If the URL starts with "dart:" then it is considered as a special
+  // library URL which is handled differently from other URLs.
+  return (strncmp(url_name, kDartScheme, kDartSchemeLen) == 0);
+}
+
+
+Dart_Handle DartUtils::CanonicalizeURL(CommandLineOptions* url_mapping,
+                                       Dart_Handle library,
+                                       const char* url_str) {
+  // 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_str = NULL;
+  Dart_Handle result = Dart_StringToCString(library_url, &library_url_str);
+  if (Dart_IsError(result)) {
+    return Dart_Error("accessing library url characters failed");
+  }
+  if (url_mapping != NULL) {
+    const char* mapped_library_url_str = MapLibraryUrl(url_mapping,
+                                                       library_url_str);
+    if (mapped_library_url_str != NULL) {
+      library_url_str = mapped_library_url_str;
+    }
+  }
+  // Calculate the canonical path.
+  const char* canon_url_str = GetCanonicalPath(library_url_str, url_str);
+  Dart_Handle canon_url = Dart_NewString(canon_url_str);
+  free(const_cast<char*>(canon_url_str));
+
+  return canon_url;
+}
+
+
+Dart_Handle DartUtils::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 DartUtils::LoadSource(CommandLineOptions* url_mapping,
+                                  Dart_Handle library,
+                                  Dart_Handle url,
+                                  Dart_LibraryTag tag,
+                                  const char* url_string) {
+  if (url_mapping != NULL && IsDartSchemeURL(url_string)) {
+    const char* mapped_url_string = MapLibraryUrl(url_mapping, url_string);
+    if (mapped_url_string == NULL) {
+      return Dart_Error("Do not know how to load %s", url_string);
+    }
+    // We have a URL mapping specified, just read the file that the
+    // URL mapping specifies and load it.
+    url_string = mapped_url_string;
+  }
+  // The tag is either an import or a source tag.
+  // Read the file and load it according to the specified tag.
+  Dart_Handle source = DartUtils::ReadStringFromFile(url_string);
+  if (Dart_IsError(source)) {
+    return source;  // source contains the error string.
+  }
+  if (tag == kImportTag) {
+    // Return library object or an error string.
+    return Dart_LoadLibrary(url, source);
+  } else if (tag == kSourceTag) {
+    return Dart_LoadSource(library, url, source);
+  }
+  return Dart_Error("wrong tag");
+}
+
+
+const char* DartUtils::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;
+}