Standardize errno's from a few dart:io File and Link calls

runtime/bin/file_macos.cc

Index: runtime/bin/file_macos.cc
diff --git a/runtime/bin/file_macos.cc b/runtime/bin/file_macos.cc
index 4556b6bbd2c0dda71cbcc1311242ccafed573ca7..767908ec6066cbec29160ca1b459cd55f8ae3f34 100644
--- a/runtime/bin/file_macos.cc
+++ b/runtime/bin/file_macos.cc
@@ -268,65 +268,79 @@ bool File::CreateLink(const char* name, const char* target) {
 }
 
 
-bool File::Delete(const char* name) {
-  File::Type type = File::GetType(name, true);
-  if (type == kIsFile) {
-    return NO_RETRY_EXPECTED(unlink(name)) == 0;
-  } else if (type == kIsDirectory) {
-    errno = EISDIR;
+File::Type File::GetType(const char* pathname, bool follow_links) {
+  struct stat entry_info;
+  int stat_success;
+  if (follow_links) {
+    stat_success = NO_RETRY_EXPECTED(stat(pathname, &entry_info));
   } else {
-    errno = ENOENT;
+    stat_success = NO_RETRY_EXPECTED(lstat(pathname, &entry_info));
   }
-  return false;
+  if (stat_success == -1) {
+    return File::kDoesNotExist;
+  }
+  if (S_ISDIR(entry_info.st_mode)) {
+    return File::kIsDirectory;
+  }
+  if (S_ISREG(entry_info.st_mode)) {
+    return File::kIsFile;
+  }
+  if (S_ISLNK(entry_info.st_mode)) {
+    return File::kIsLink;
+  }
+  return File::kDoesNotExist;
 }
 
 
-bool File::DeleteLink(const char* name) {
-  File::Type type = File::GetType(name, false);
-  if (type == kIsLink) {
-    return NO_RETRY_EXPECTED(unlink(name)) == 0;
+static bool CheckTypeAndSetErrno(const char* name,
+                                 File::Type expected,
+                                 bool follow_links) {
+  File::Type actual = File::GetType(name, follow_links);
+  if (actual == expected) {
+    return true;
+  }
+  switch (actual) {
+    case File::kIsDirectory:
+      errno = EISDIR;
+      break;
+    case File::kDoesNotExist:
+      errno = ENOENT;
+      break;
+    default:
+      errno = EINVAL;
+      break;
   }
-  errno = EINVAL;
   return false;
 }
 
 
+bool File::Delete(const char* name) {
+  return CheckTypeAndSetErrno(name, kIsFile, true) &&
+         (NO_RETRY_EXPECTED(unlink(name)) == 0);
+}
+
+
+bool File::DeleteLink(const char* name) {
+  return CheckTypeAndSetErrno(name, kIsLink, false) &&
+         (NO_RETRY_EXPECTED(unlink(name)) == 0);
+}
+
+
 bool File::Rename(const char* old_path, const char* new_path) {
-  File::Type type = File::GetType(old_path, true);
-  if (type == kIsFile) {
-    return NO_RETRY_EXPECTED(rename(old_path, new_path)) == 0;
-  } else if (type == kIsDirectory) {
-    errno = EISDIR;
-  } else {
-    errno = ENOENT;
-  }
-  return false;
+  return CheckTypeAndSetErrno(old_path, kIsFile, true) &&
+         (NO_RETRY_EXPECTED(rename(old_path, new_path)) == 0);
 }
 
 
 bool File::RenameLink(const char* old_path, const char* new_path) {
-  File::Type type = File::GetType(old_path, false);
-  if (type == kIsLink) {
-    return NO_RETRY_EXPECTED(rename(old_path, new_path)) == 0;
-  } else if (type == kIsDirectory) {
-    errno = EISDIR;
-  } else {
-    errno = EINVAL;
-  }
-  return false;
+  return CheckTypeAndSetErrno(old_path, kIsLink, false) &&
+         (NO_RETRY_EXPECTED(rename(old_path, new_path)) == 0);
 }
 
 
 bool File::Copy(const char* old_path, const char* new_path) {
-  File::Type type = File::GetType(old_path, true);
-  if (type == kIsFile) {
-    return copyfile(old_path, new_path, NULL, COPYFILE_ALL) == 0;
-  } else if (type == kIsDirectory) {
-    errno = EISDIR;
-  } else {
-    errno = ENOENT;
-  }
-  return false;
+  return CheckTypeAndSetErrno(old_path, kIsFile, true) &&
+         (copyfile(old_path, new_path, NULL, COPYFILE_ALL) == 0);
 }
 
 
@@ -477,30 +491,6 @@ File::StdioHandleType File::GetStdioHandleType(int fd) {
 }
 
 
-File::Type File::GetType(const char* pathname, bool follow_links) {
-  struct stat entry_info;
-  int stat_success;
-  if (follow_links) {
-    stat_success = NO_RETRY_EXPECTED(stat(pathname, &entry_info));
-  } else {
-    stat_success = NO_RETRY_EXPECTED(lstat(pathname, &entry_info));
-  }
-  if (stat_success == -1) {
-    return File::kDoesNotExist;
-  }
-  if (S_ISDIR(entry_info.st_mode)) {
-    return File::kIsDirectory;
-  }
-  if (S_ISREG(entry_info.st_mode)) {
-    return File::kIsFile;
-  }
-  if (S_ISLNK(entry_info.st_mode)) {
-    return File::kIsLink;
-  }
-  return File::kDoesNotExist;
-}
-
-
 File::Identical File::AreIdentical(const char* file_1, const char* file_2) {
   struct stat file_1_info;
   struct stat file_2_info;