[PATCH v5 02/44] wrapper: implement xfopen()
From: Paul Tan <hidden>
Date: 2016-06-15 23:05:41
Subsystem:
the rest · Maintainer:
Linus Torvalds
A common usage pattern of fopen() is to check if it succeeded, and die()
if it failed:
FILE *fp = fopen(path, "w");
if (!fp)
die_errno(_("could not open '%s' for writing"), path);
Implement a wrapper function xfopen() for the above, so that we can save
a few lines of code and make the die() messages consistent.
Helped-by: Jeff King [off-list ref]
Helped-by: Johannes Schindelin [off-list ref]
Helped-by: Junio C Hamano [off-list ref]
Signed-off-by: Paul Tan <redacted>
---
Notes:
v5
* Removed assert()s since we do not need to over-zealously guard against
insane code.
* The read/write error messages have returned as they are useful in
diagnosing permission errors. Hopefully I got the logic right this
time.
git-compat-util.h | 1 +
wrapper.c | 21 +++++++++++++++++++++
2 files changed, 22 insertions(+)
diff --git a/git-compat-util.h b/git-compat-util.h
index e168dfd..392da79 100644
--- a/git-compat-util.h
+++ b/git-compat-util.h@@ -722,6 +722,7 @@ extern ssize_t xread(int fd, void *buf, size_t len); extern ssize_t xwrite(int fd, const void *buf, size_t len); extern ssize_t xpread(int fd, void *buf, size_t len, off_t offset); extern int xdup(int fd); +extern FILE *xfopen(const char *path, const char *mode); extern FILE *xfdopen(int fd, const char *mode); extern int xmkstemp(char *template); extern int xmkstemp_mode(char *template, int mode);
diff --git a/wrapper.c b/wrapper.c
index 0a4502d..e451463 100644
--- a/wrapper.c
+++ b/wrapper.c@@ -346,6 +346,27 @@ int xdup(int fd) return ret; } +/** + * xfopen() is the same as fopen(), but it die()s if the fopen() fails. + */ +FILE *xfopen(const char *path, const char *mode) +{ + for (;;) { + FILE *fp = fopen(path, mode); + if (fp) + return fp; + if (errno == EINTR) + continue; + + if (*mode && mode[1] == '+') + die_errno(_("could not open '%s' for reading and writing"), path); + else if (*mode == 'w' || *mode == 'a') + die_errno(_("could not open '%s' for writing"), path); + else + die_errno(_("could not open '%s' for reading"), path); + } +} + FILE *xfdopen(int fd, const char *mode) { FILE *stream = fdopen(fd, mode);
--
2.5.0.rc1.76.gf60a929