[modules] Add basic path normalization to d8's module loader

src/d8.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <errno.h>
 #include <stdlib.h>
 #include <string.h>
 #include <sys/stat.h>
 
 #include <algorithm>
@@ skipping 535 matching lines @@
 }
 
 // Returns the directory part of path, without the trailing '/'.
 std::string DirName(const std::string& path) {
   DCHECK(IsAbsolutePath(path));
   size_t last_slash = path.find_last_of('/');
   DCHECK(last_slash != std::string::npos);
   return path.substr(0, last_slash);
 }
 
-std::string EnsureAbsolutePath(const std::string& path,
-                               const std::string& dir_name) {
-  return IsAbsolutePath(path) ? path : dir_name + '/' + path;
+// Resolves path to an absolute path if necessary, and do some

[neis, 2016/10/06 07:18:29]

s/do/does/

[adamk, 2016/10/06 18:50:38]

Done.

+// normalization (eliding references to the current directory
+// and replacing backslashes with slashes).
+std::string NormalizePath(const std::string& path,
+                          const std::string& dir_name) {
+  std::string result;
+  if (IsAbsolutePath(path)) {
+    result = path;
+  } else {
+    result = dir_name + '/' + path;
+  }
+  size_t i;
+  while ((i = result.find("/./")) != std::string::npos) {
+    result.erase(i, 2);
+  }
+  std::replace(result.begin(), result.end(), '\\', '/');

[neis, 2016/10/06 07:18:29]

Don't you want to do the replace before searching for /./ ?

[adamk, 2016/10/06 18:50:38]

Done.

+  return result;
 }
 
 MaybeLocal<Module> ResolveModuleCallback(Local<Context> context,
                                          Local<String> specifier,
                                          Local<Module> referrer,
                                          Local<Value> data) {
   Isolate* isolate = context->GetIsolate();
   auto module_map = static_cast<std::map<std::string, Global<Module>>*>(
       External::Cast(*data)->Value());
   Local<String> dir_name = Local<String>::Cast(referrer->GetEmbedderData());
   std::string absolute_path =
-      EnsureAbsolutePath(ToSTLString(specifier), ToSTLString(dir_name));
+      NormalizePath(ToSTLString(specifier), ToSTLString(dir_name));
   auto it = module_map->find(absolute_path);
   if (it != module_map->end()) {
     return it->second.Get(isolate);
   }
   return MaybeLocal<Module>();
 }
 
 }  // anonymous namespace
 
 MaybeLocal<Module> Shell::FetchModuleTree(
@@ skipping 19 matching lines @@
   module_map->insert(
       std::make_pair(file_name, Global<Module>(isolate, module)));
 
   std::string dir_name = DirName(file_name);
   module->SetEmbedderData(
       String::NewFromUtf8(isolate, dir_name.c_str(), NewStringType::kNormal)
           .ToLocalChecked());
 
   for (int i = 0, length = module->GetModuleRequestsLength(); i < length; ++i) {
     Local<String> name = module->GetModuleRequest(i);
-    std::string absolute_path = EnsureAbsolutePath(ToSTLString(name), dir_name);
+    std::string absolute_path = NormalizePath(ToSTLString(name), dir_name);
     if (!module_map->count(absolute_path)) {
       if (FetchModuleTree(isolate, absolute_path, module_map).IsEmpty()) {
         return MaybeLocal<Module>();
       }
     }
   }
 
   return module;
 }
 
 bool Shell::ExecuteModule(Isolate* isolate, const char* file_name) {
   HandleScope handle_scope(isolate);
 
-  std::string absolute_path =
-      EnsureAbsolutePath(file_name, GetWorkingDirectory());
-  std::replace(absolute_path.begin(), absolute_path.end(), '\\', '/');
+  std::string absolute_path = NormalizePath(file_name, GetWorkingDirectory());
 
   Local<Module> root_module;
   std::map<std::string, Global<Module>> module_map;
   if (!FetchModuleTree(isolate, absolute_path, &module_map)
            .ToLocal(&root_module)) {
     return false;
   }
 
   TryCatch try_catch(isolate);
   try_catch.SetVerbose(true);
@@ skipping 2115 matching lines @@
 }
 
 }  // namespace v8
 
 
 #ifndef GOOGLE3
 int main(int argc, char* argv[]) {
   return v8::Shell::Main(argc, argv);
 }
 #endif