Mapping file busy/exists in POSIX File::OSErrorToFileError().

base/files/file_posix.cc

Index: base/files/file_posix.cc
diff --git a/base/files/file_posix.cc b/base/files/file_posix.cc
index 245ea6a8ebddf2f5b19f9aaa41f5ae8c1315ef17..ab2e5932f6238bc879f6e3eec75e8256a02adb31 100644
--- a/base/files/file_posix.cc
+++ b/base/files/file_posix.cc
@@ -471,12 +471,16 @@ File::Error File::OSErrorToFileError(int saved_errno) {
     case EROFS:
     case EPERM:
       return FILE_ERROR_ACCESS_DENIED;
+    case EBUSY:

[rvargas (doing something else), 2015/03/12 22:10:57]

My guess is that this is also not defined by NaCl.

[cmumford, 2015/03/12 22:41:32]

Looks like EBUSY *is* supported. Lots of matches in native_client_sdk/**.cc. The
PNACL team seems to think it's supported too. ETXTBUSY is not in there (which
agrees with the current implementation), and to be safe I verified that EIO is
supported.

I'm also a little confused why we ETXTBUSY is #ifdef'ed out. Sure NaCL never
set's errno to this value, but if that ever changes then we'll stop mapping the
value. Why not just map it (but have a comment saying it'll probably never be
seen)?

[rvargas (doing something else), 2015/03/12 22:58:07]

My impression is that they wanted to provide a strict subset of functionality
and wanted to make sure the compiler would complain as soon as possible.

I would be happy to see ifdefs disappear but that's another discussion :)

+      return FILE_ERROR_IN_USE;
 #if !defined(OS_NACL)  // ETXTBSY not defined by NaCl.
     case ETXTBSY:

[rvargas (doing something else), 2015/03/12 22:58:07]

nit: Given that this is staying, we should probably write the code as we
normally would and wrap only this line with an ifdef.

       return FILE_ERROR_IN_USE;
 #endif
     case EEXIST:
       return FILE_ERROR_EXISTS;
+    case EIO:
+      return FILE_ERROR_IO;
     case ENOENT:
       return FILE_ERROR_NOT_FOUND;
     case EMFILE: