Error reporting on File in dart:io

runtime/bin/file_linux.cc

Index: runtime/bin/file_linux.cc
diff --git a/runtime/bin/file_linux.cc b/runtime/bin/file_linux.cc
index 409f31c8800b4f5e0eee3d3c790a71d101729d9e..21e6825da5a573486dbb4958038f84a8881854da 100644
--- a/runtime/bin/file_linux.cc
+++ b/runtime/bin/file_linux.cc
@@ -105,6 +105,13 @@ off_t File::Length() {
 
 
 File* File::Open(const char* name, FileOpenMode mode) {
+  struct stat st;
+  if (TEMP_FAILURE_RETRY(stat(name, &st)) == 0) {

[Mads Ager (google), 2012/03/13 10:56:17]

Why do you need this? Isn't the error code from open enough?

[Søren Gjesse, 2012/03/13 12:39:49]

This is to avoid opening non-regular files. Before we used exists in Dart before
calling opne to avoid opening directories, and other "special" files, but using
can eat the actual error we want to report.

We could also just allow opening directories and special files.

Added comment.

+    if (!S_ISREG(st.st_mode)) {
+      errno = (S_ISDIR(st.st_mode)) ? EISDIR : ENOENT;
+      return false;

[Mads Ager (google), 2012/03/13 10:56:17]

false -> NULL

[Søren Gjesse, 2012/03/13 12:39:49]

Good catch, done.

+    }
+  }
   int flags = O_RDONLY;
   if ((mode & kWrite) != 0) {
     flags = (O_RDWR | O_CREAT);
@@ -178,6 +185,15 @@ char* File::GetCanonicalPath(const char* pathname) {
 
 
 char* File::GetContainingDirectory(char* pathname) {
+  struct stat st;
+  if (TEMP_FAILURE_RETRY(stat(pathname, &st)) == 0) {

[Mads Ager (google), 2012/03/13 10:56:17]

Similarly here, don't we get a good enough error message if we do not do this?

[Søren Gjesse, 2012/03/13 12:39:49]

As for open above we used to have an exists check in Dart. The system call
dirname is just a string operation.

Added comment.

+    if (!S_ISREG(st.st_mode)) {
+      errno = (S_ISDIR(st.st_mode)) ? EISDIR : ENOENT;
+      return NULL;
+    }
+  } else {
+    return NULL;
+  }
   char* path = NULL;
   do {
     path = dirname(pathname);