Thread (18 messages) flat view 18 messages, 5 authors, 2016-06-15

Re: [PATCH/WIP 1/8] wrapper: implement xopen()

From: Stefan Beller <hidden>
Date: 2016-06-15 23:05:01

On Wed, May 27, 2015 at 6:33 AM, Paul Tan [off-list ref] wrote:
A common usage pattern of open() is to check if it was successful, and
die() if it was not:

        int fd = open(path, O_WRONLY | O_CREAT, 0777);
        if (fd < 0)
                die_errno(_("Could not open '%s' for writing."), path);

Implement a wrapper function xopen() that does the above so that we can
save a few lines of code, and make the die() messages consistent.
As a mental todo note for whomever wants to pick up some work: This patch
series indicates to only touch git-am. The first 2 patches introduce
new x-wrappers,
so maybe we'd need to grep through the whole code base and convert the all
these file opening code to the new wrapper.
quoted hunk ↗ jump to hunk
Signed-off-by: Paul Tan <redacted>
---
 git-compat-util.h |  1 +
 wrapper.c         | 18 ++++++++++++++++++
 2 files changed, 19 insertions(+)
diff --git a/git-compat-util.h b/git-compat-util.h
index 17584ad..9745962 100644
--- a/git-compat-util.h
+++ b/git-compat-util.h
@@ -718,6 +718,7 @@ extern char *xstrndup(const char *str, size_t len);
 extern void *xrealloc(void *ptr, size_t size);
 extern void *xcalloc(size_t nmemb, size_t size);
 extern void *xmmap(void *start, size_t length, int prot, int flags, int fd, off_t offset);
+extern int xopen(const char *path, int flags, mode_t mode);
 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);
diff --git a/wrapper.c b/wrapper.c
index c1a663f..971665a 100644
--- a/wrapper.c
+++ b/wrapper.c
@@ -189,6 +189,24 @@ void *xcalloc(size_t nmemb, size_t size)
 # endif
 #endif

+/**
+ * xopen() is the same as open(), but it die()s if the open() fails.
+ */
+int xopen(const char *path, int flags, mode_t mode)
+{
+       int fd;
+
+       assert(path);
+       fd = open(path, flags, mode);
+       if (fd < 0) {
+               if ((flags & O_WRONLY) || (flags & O_RDWR))
+                       die_errno(_("could not open '%s' for writing"), path);
+               else
+                       die_errno(_("could not open '%s' for reading"), path);
+       }
+       return fd;
+}
+
 /*
  * xread() is the same a read(), but it automatically restarts read()
  * operations with a recoverable error (EAGAIN and EINTR). xread()
--
2.1.4
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