Author: cem Date: Wed Aug 7 19:27:14 2019 New Revision: 350693 URL: https://svnweb.freebsd.org/changeset/base/350693
Log: sbuf(9): Add sbuf_nl_terminate() API The API is used to gracefully terminate text line(s) with a single \n. If the formatted buffer was empty or already ended in \n, it is unmodified. Otherwise, a newline character is appended to it. The API, like other sbuf-modifying routines, is only valid while the sbuf is not FINISHED. Reviewed by: rlibby Sponsored by: Dell EMC Isilon Differential Revision: https://reviews.freebsd.org/D21030 Modified: head/share/man/man9/sbuf.9 head/sys/kern/subr_sbuf.c head/sys/sys/sbuf.h Modified: head/share/man/man9/sbuf.9 ============================================================================== --- head/share/man/man9/sbuf.9 Wed Aug 7 19:25:56 2019 (r350692) +++ head/share/man/man9/sbuf.9 Wed Aug 7 19:27:14 2019 (r350693) @@ -44,6 +44,7 @@ .Nm sbuf_cat , .Nm sbuf_copyin , .Nm sbuf_cpy , +.Nm sbuf_nl_terminate , .Nm sbuf_printf , .Nm sbuf_vprintf , .Nm sbuf_putc , @@ -123,6 +124,8 @@ .Fa "const char *str" .Fc .Ft int +.Fn sbuf_nl_terminate "struct sbuf *" +.Ft int .Fo sbuf_printf .Fa "struct sbuf *s" .Fa "const char *fmt" "..." @@ -440,10 +443,14 @@ To do unbuffered draining, initialize the sbuf with a The drain will be called for every byte added to the sbuf. The .Fn sbuf_bcopyin , +.Fn sbuf_bcpy , +.Fn sbuf_clear , .Fn sbuf_copyin , +.Fn sbuf_cpy , .Fn sbuf_trim , +.Fn sbuf_data , and -.Fn sbuf_data +.Fn sbuf_len functions cannot be used on an sbuf with a drain. .Pp The @@ -474,6 +481,11 @@ or one which position has been reset to zero with .Fn sbuf_clear or .Fn sbuf_setpos . +.Pp +The +.Fn sbuf_nl_terminate +function appends a trailing newline character, if the current line is non-empty +and not already terminated by a newline character. .Pp The .Fn sbuf_printf Modified: head/sys/kern/subr_sbuf.c ============================================================================== --- head/sys/kern/subr_sbuf.c Wed Aug 7 19:25:56 2019 (r350692) +++ head/sys/kern/subr_sbuf.c Wed Aug 7 19:27:14 2019 (r350693) @@ -70,6 +70,7 @@ static MALLOC_DEFINE(M_SBUF, "sbuf", "string buffers") #define SBUF_ISDYNAMIC(s) ((s)->s_flags & SBUF_DYNAMIC) #define SBUF_ISDYNSTRUCT(s) ((s)->s_flags & SBUF_DYNSTRUCT) #define SBUF_ISFINISHED(s) ((s)->s_flags & SBUF_FINISHED) +#define SBUF_ISDRAINATEOL(s) ((s)->s_flags & SBUF_DRAINATEOL) #define SBUF_HASROOM(s) ((s)->s_len < (s)->s_size - 1) #define SBUF_FREESPACE(s) ((s)->s_size - ((s)->s_len + 1)) #define SBUF_CANEXTEND(s) ((s)->s_flags & SBUF_AUTOEXTEND) @@ -225,6 +226,10 @@ sbuf_new(struct sbuf *s, char *buf, int length, int fl s->s_flags |= flags; s->s_size = length; s->s_buf = buf; + /* + * Never-written sbufs do not need \n termination. + */ + SBUF_SETFLAG(s, SBUF_DRAINATEOL); /* * Allocate DYNAMIC, i.e., heap data buffer backing the sbuf, if no @@ -310,6 +315,8 @@ sbuf_clear(struct sbuf *s) assert_sbuf_integrity(s); /* don't care if it's finished or not */ + KASSERT(s->s_drain_func == NULL, + ("%s makes no sense on sbuf %p with drain", __func__, s)); SBUF_CLEARFLAG(s, SBUF_FINISHED); s->s_error = 0; @@ -384,6 +391,7 @@ sbuf_drain(struct sbuf *s) KASSERT(s->s_len > 0, ("Shouldn't drain empty sbuf %p", s)); KASSERT(s->s_error == 0, ("Called %s with error on %p", __func__, s)); + if (SBUF_DODRAINTOEOR(s) && s->s_rec_off == 0) return (s->s_error = EDEADLK); len = s->s_drain_func(s->s_drain_arg, s->s_buf, @@ -400,8 +408,18 @@ sbuf_drain(struct sbuf *s) * Fast path for the expected case where all the data was * drained. */ - if (s->s_len == 0) + if (s->s_len == 0) { + /* + * When the s_buf is entirely drained, we need to remember if + * the last character was a '\n' or not for + * sbuf_nl_terminate(). + */ + if (s->s_buf[len - 1] == '\n') + SBUF_SETFLAG(s, SBUF_DRAINATEOL); + else + SBUF_CLEARFLAG(s, SBUF_DRAINATEOL); return (0); + } /* * Move the remaining characters to the beginning of the * string. @@ -711,6 +729,38 @@ sbuf_putc(struct sbuf *s, int c) { sbuf_put_byte(s, c); + if (s->s_error != 0) + return (-1); + return (0); +} + +/* + * Append a trailing newline to a non-empty sbuf, if one is not already + * present. Handles sbufs with drain functions correctly. + */ +int +sbuf_nl_terminate(struct sbuf *s) +{ + + assert_sbuf_integrity(s); + assert_sbuf_state(s, 0); + + /* + * If the s_buf isn't empty, the last byte is simply s_buf[s_len - 1]. + * + * If the s_buf is empty because a drain function drained it, we + * remember if the last byte was a \n with the SBUF_DRAINATEOL flag in + * sbuf_drain(). + * + * In either case, we only append a \n if the previous character was + * something else. + */ + if (s->s_len == 0) { + if (!SBUF_ISDRAINATEOL(s)) + sbuf_put_byte(s, '\n'); + } else if (s->s_buf[s->s_len - 1] != '\n') + sbuf_put_byte(s, '\n'); + if (s->s_error != 0) return (-1); return (0); Modified: head/sys/sys/sbuf.h ============================================================================== --- head/sys/sys/sbuf.h Wed Aug 7 19:25:56 2019 (r350692) +++ head/sys/sys/sbuf.h Wed Aug 7 19:27:14 2019 (r350693) @@ -58,6 +58,7 @@ struct sbuf { #define SBUF_FINISHED 0x00020000 /* set by sbuf_finish() */ #define SBUF_DYNSTRUCT 0x00080000 /* sbuf must be freed */ #define SBUF_INSECTION 0x00100000 /* set by sbuf_start_section() */ +#define SBUF_DRAINATEOL 0x00200000 /* drained contents ended in \n */ int s_flags; /* flags */ ssize_t s_sect_len; /* current length of section */ ssize_t s_rec_off; /* current record start offset */ @@ -91,6 +92,7 @@ int sbuf_printf(struct sbuf *, const char *, ...) __printflike(2, 3); int sbuf_vprintf(struct sbuf *, const char *, __va_list) __printflike(2, 0); +int sbuf_nl_terminate(struct sbuf *); int sbuf_putc(struct sbuf *, int); void sbuf_set_drain(struct sbuf *, sbuf_drain_func *, void *); int sbuf_trim(struct sbuf *); _______________________________________________ svn-src-all@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-all To unsubscribe, send any mail to "svn-src-all-unsubscr...@freebsd.org"
