On Fri, Jan 30 2015, Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> wrote: > On Thu, 2015-01-29 at 15:29 +0100, Rasmus Villemoes wrote: >> On Thu, Jan 29 2015, Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> wrote: >> >> >> * >> >> * Return: >> >> - * The amount of the characters processed to the destination buffer, or >> >> - * %-ENOMEM if the size of buffer is not enough to put an escaped character is >> >> - * returned. >> >> - * >> >> - * Even in the case of error @dst pointer will be updated to point to the byte >> >> - * after the last processed character. >> >> + * The total size of the escaped output that would be generated for >> >> + * the given input and flags. To check whether the output was >> >> + * truncated, compare the return value to osz. There is room left in >> >> + * dst for a '\0' terminator if and only if ret < osz. >> >> */ >> >> -int string_escape_mem(const char *src, size_t isz, char **dst, size_t osz, >> >> - unsigned int flags, const char *esc) >> >> +size_t string_escape_mem(const char *src, size_t isz, char *dst, size_t osz, >> >> + unsigned int flags, const char *esc) >> > >> > I prefer to leave the prototype the same. int for return is okay. dst >> > should be updated accordingly. >> >> Please explain exactly what you think the return value should be, and >> what *dst should be set to. > > Return value like you proposed, *dst is incremented by it. The more I think about it, the less I like having dst being char**. (1) It is unlike most other functions taking buffer+size arguments. (2) It is inconvenient. Callers doing char escaped[SOME_SIZE]; or char *escaped = kmalloc(likely_big_enough); can't just pass &escaped; they would need to use an extra dummy variable. (3) With the return value telling the size of the would-be generated output, it is redundant. In fact, I dislike it so much that I'm not going to sign off on a patch where dst is still char**. >> > Could it be a part of nomem test still? >> >> What nomem test? string_escape_mem with snprintf-like semantics cannot >> return an error; that has to be checked by the caller. > > Make this code a separate test, which actually still nomem, since you > have not enough memory in the destination buffer. What the problem to > check for proper return value and the last couple of characters written > to the destination buffer? Sure, it could go into a separate helper. Anyway, the semantics of string_escape_mem needs to be decided before it makes sense to update the tests. > When your series will be ready (and actually I recommend to push first > patch apart from the rest since it's not related) I agree on that part. Andrew, could you take 1/3 (http://thread.gmane.org/gmane.linux.kernel/1876841/focus=348404), and then we'll see when the %pE case gets sorted out. Rasmus -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
