virstring: Introduce VIR_STRDUP and VIR_STRNDUP

The code adaptation is not done right now, but in subsequent patches.
Hence I am not implementing syntax-check rule as it would break
compilation. Developers are strongly advised to use these new macros.
They are similar to VIR_ALLOC() logic: VIR_STRDUP(dst, src) returns zero
on success, -1 otherwise. In case you don't want to report OOM error,
use the _QUIET variant of a macro.
This commit is contained in:
Michal Privoznik 2013-04-03 14:51:20 +02:00
parent b1434b36b1
commit c3abb5c459
5 changed files with 163 additions and 0 deletions

11
HACKING
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@ -719,6 +719,17 @@ sizeof(dest) returns something meaningful). Note that this is a macro, so
arguments could be evaluated more than once. This is equivalent to
virStrncpy(dest, src, strlen(src), sizeof(dest)).
VIR_STRDUP(char *dst, const char *src);
VIR_STRNDUP(char *dst, const char *src, size_t n);
You should avoid using strdup or strndup directly as they do not report
out-of-memory error. Use VIR_STRDUP or VIR_STRNDUP macros instead. Note, that
these two behave similar to VIR_ALLOC: on success zero is returned, otherwise
the result is -1 and dst is guaranteed to be NULL. In very specific cases,
when you don't want to report the out-of-memory error, you can use
VIR_STRDUP_QUIET or VIR_STRNDUP_QUIET, but such usage is very rare and usually
considered a flaw.
Variable length string buffer
=============================

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@ -855,6 +855,20 @@
virStrncpy(dest, src, strlen(src), sizeof(dest)).
</p>
<pre>
VIR_STRDUP(char *dst, const char *src);
VIR_STRNDUP(char *dst, const char *src, size_t n);
</pre>
<p>
You should avoid using strdup or strndup directly as they do not report
out-of-memory error. Use VIR_STRDUP or VIR_STRNDUP macros instead. Note,
that these two behave similar to VIR_ALLOC: on success zero is returned,
otherwise the result is -1 and dst is guaranteed to be NULL. In very
specific cases, when you don't want to report the out-of-memory error, you
can use VIR_STRDUP_QUIET or VIR_STRNDUP_QUIET, but such usage is very rare
and usually considered a flaw.
</p>
<h2><a name="strbuf">Variable length string buffer</a></h2>
<p>

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@ -1751,11 +1751,13 @@ virSkipSpaces;
virSkipSpacesAndBackslash;
virSkipSpacesBackwards;
virStrcpy;
virStrdup;
virStringArrayHasString;
virStringFreeList;
virStringJoin;
virStringSplit;
virStrncpy;
virStrndup;
virStrToDouble;
virStrToLong_i;
virStrToLong_l;

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@ -515,3 +515,77 @@ virArgvToString(const char *const *argv)
return ret;
}
/**
* virStrdup:
* @dest: where to store duplicated string
* @src: the source string to duplicate
* @report: whether to report OOM error, if there is one
* @domcode: error domain code
* @filename: caller's filename
* @funcname: caller's funcname
* @linenr: caller's line number
*
* Wrapper over strdup, which reports OOM error if told so,
* in which case callers wants to pass @domcode, @filename,
* @funcname and @linenr which should represent location in
* caller's body where virStrdup is called from. Consider
* using VIR_STRDUP which sets these automatically.
*
* Returns: 0 on success, -1 otherwise.
*/
int
virStrdup(char **dest,
const char *src,
bool report,
int domcode,
const char *filename,
const char *funcname,
size_t linenr)
{
if (!(*dest = strdup(src))) {
if (report)
virReportOOMErrorFull(domcode, filename, funcname, linenr);
return -1;
}
return 0;
}
/**
* virStrndup:
* @dest: where to store duplicated string
* @src: the source string to duplicate
* @n: how many bytes to copy
* @report: whether to report OOM error, if there is one
* @domcode: error domain code
* @filename: caller's filename
* @funcname: caller's funcname
* @linenr: caller's line number
*
* Wrapper over strndup, which reports OOM error if told so,
* in which case callers wants to pass @domcode, @filename,
* @funcname and @linenr which should represent location in
* caller's body where virStrndup is called from. Consider
* using VIR_STRNDUP which sets these automatically.
*
* Returns: 0 on success, -1 otherwise.
*/
int
virStrndup(char **dest,
const char *src,
size_t n,
bool report,
int domcode,
const char *filename,
const char *funcname,
size_t linenr)
{
if (!(*dest = strndup(src, n))) {
if (report)
virReportOOMErrorFull(domcode, filename, funcname, linenr);
return -1;
}
return 0;
}

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@ -87,4 +87,66 @@ char *virStrncpy(char *dest, const char *src, size_t n, size_t destbytes)
char *virStrcpy(char *dest, const char *src, size_t destbytes)
ATTRIBUTE_RETURN_CHECK;
# define virStrcpyStatic(dest, src) virStrcpy((dest), (src), sizeof(dest))
/* Don't call these directly - use the macros below */
int virStrdup(char **dest, const char *src, bool report, int domcode,
const char *filename, const char *funcname, size_t linenr)
ATTRIBUTE_RETURN_CHECK ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2);
int virStrndup(char **dest, const char *src, size_t n, bool report, int domcode,
const char *filename, const char *funcname, size_t linenr)
ATTRIBUTE_RETURN_CHECK ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2);
/**
* VIR_STRDUP:
* @dst: variable to hold result (char*, not char**)
* @src: string to duplicate
*
* Duplicate @src string and store it into @dst.
*
* Returns -1 on failure (with OOM error reported), 0 on success
*/
# define VIR_STRDUP(dst, src) virStrdup(&(dst), src, true, VIR_FROM_THIS, \
__FILE__, __FUNCTION__, __LINE__)
/**
* VIR_STRDUP_QUIET:
* @dst: variable to hold result (char*, not char**)
* @src: string to duplicate
*
* Duplicate @src string and store it into @dst.
*
* Returns -1 on failure, 0 on success
*/
# define VIR_STRDUP_QUIET(dst, src) virStrdup(&(dst), src, false, 0, NULL, NULL, 0)
/**
* VIR_STRNDUP:
* @dst: variable to hold result (char*, not char**)
* @src: string to duplicate
* @n: the maximum number of bytes to copy
*
* Duplicate @src string and store it into @dst. If @src is longer than @n,
* only @n bytes are copied and terminating null byte '\0' is added.
*
* Returns -1 on failure (with OOM error reported), 0 on success
*/
# define VIR_STRNDUP(dst, src, n) virStrndup(&(dst), src, n, true, \
VIR_FROM_THIS, __FILE__, \
__FUNCTION__, __LINE__)
/**
* VIR_STRNDUP_QUIET:
* @dst: variable to hold result (char*, not char**)
* @src: string to duplicate
* @n: the maximum number of bytes to copy
*
* Duplicate @src string and store it into @dst. If @src is longer than @n,
* only @n bytes are copied and terminating null byte '\0' is added.
*
* Returns -1 on failure, 0 on success
*/
# define VIR_STRNDUP_QUIET(dst, src, n) virStrndup(&(dst), src, n, false, \
0, NULL, NULL, 0)
#endif /* __VIR_STRING_H__ */