[PATCH 3/5] strbuf: provide CRLF-aware helper to read until a specified delimiter
- From
Patrick Steinhardt <ps@pks.im>
- Date
- Jun 2, 2023, 13:02 UTC
- Message-ID
- <8127eeac97200da9aafccdf16cb7ba06f68b0121.1685710884.git.ps@pks.im>
- In-Reply-To
- <cover.1685710884.git.ps@pks.im>
Many of our commands support reading input that is separated either via newlines or via NUL characters. Furthermore, in order to be a better cross platform citizen, these commands typically know to strip the CRLF sequence so that we also support reading newline-separated inputs on e.g. the Windows platform. This results in the following kind of awkward pattern:
``` struct strbuf input = STRBUF_INIT;
while (1) {
int ret;if (nul_terminated) ret = strbuf_getline_nul(&input, stdin); else ret = strbuf_getline(&input, stdin); if (ret) break;
... } ```
Introduce a new CRLF-aware helper function that can read up to a user specified delimiter. If the delimiter is `\n` the function knows to also strip CRLF, otherwise it will only strip the specified delimiter. This results in the following, much more readable code pattern:
``` struct strbuf input = STRBUF_INIT;
while (strbuf_getdelim_strip_crlf(&input, stdin, delim) != EOF) {
...
}
```The new function will be used in a subsequent commit.
Signed-off-by: Patrick Steinhardt <ps@pks.im> --- strbuf.c | 11 ++++++++--- strbuf.h | 12 ++++++++++++ 2 files changed, 20 insertions(+), 3 deletions(-)
diff --git a/strbuf.c b/strbuf.c index 08eec8f1d8..31dc48c0ab 100644 --- a/strbuf.c +++ b/strbuf.c @@ -721,11 +721,11 @@ static int strbuf_getdelim(struct strbuf *sb, FILE *fp, int term) return 0; } -int strbuf_getline(struct strbuf *sb, FILE *fp) +int strbuf_getdelim_strip_crlf(struct strbuf *sb, FILE *fp, int term) { - if (strbuf_getwholeline(sb, fp, '\n')) + if (strbuf_getwholeline(sb, fp, term)) return EOF; - if (sb->buf[sb->len - 1] == '\n') { + if (term == '\n' && sb->buf[sb->len - 1] == '\n') { strbuf_setlen(sb, sb->len - 1); if (sb->len && sb->buf[sb->len - 1] == '\r') strbuf_setlen(sb, sb->len - 1); @@ -733,6 +733,11 @@ int strbuf_getline(struct strbuf *sb, FILE *fp) return 0; } +int strbuf_getline(struct strbuf *sb, FILE *fp) +{ + return strbuf_getdelim_strip_crlf(sb, fp, '\n'); +} + int strbuf_getline_lf(struct strbuf *sb, FILE *fp) { return strbuf_getdelim(sb, fp, '\n'); diff --git a/strbuf.h b/strbuf.h index 3dfeadb44c..0e69b656bc 100644 --- a/strbuf.h +++ b/strbuf.h @@ -475,6 +475,18 @@ int strbuf_readlink(struct strbuf *sb, const char *path, size_t hint); */ ssize_t strbuf_write(struct strbuf *sb, FILE *stream); +/** + * Read from a FILE * until the specified terminator is encountered, + * overwriting the existing contents of the strbuf. + * + * Reading stops after the terminator or at EOF. The terminator is + * removed from the buffer before returning. If the terminator is LF + * and if it is preceded by a CR, then the whole CRLF is stripped. + * Returns 0 unless there was nothing left before EOF, in which case + * it returns `EOF`. + */ +int strbuf_getdelim_strip_crlf(struct strbuf *sb, FILE *fp, int term); + /** * Read a line from a FILE *, overwriting the existing contents of * the strbuf. The strbuf_getline*() family of functions share
-- 2.40.1