10:51 a.m.
On Thu, Feb 23, 2017 at 04:32:32PM +0000, Daniel P. Berrange wrote:
On Thu, Feb 23, 2017 at 04:26:58PM +0100, Pavel Hrdina wrote:
> Signed-off-by: Pavel Hrdina <phrdina(a)redhat.com>
> ---
> src/libvirt_private.syms | 1 +
> src/util/virbuffer.c | 104 +++++++++++++++++++++++++++++++++++++++++++++++
> src/util/virbuffer.h | 2 +
> tests/virbuftest.c | 41 +++++++++++++++++++
> 4 files changed, 148 insertions(+)
>
> diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
> index e9c4d73779..6ce32f1101 100644
> --- a/src/libvirt_private.syms
> +++ b/src/libvirt_private.syms
> @@ -1286,6 +1286,7 @@ virBufferContentAndReset;
> virBufferCurrentContent;
> virBufferError;
> virBufferEscape;
> +virBufferEscapeN;
> virBufferEscapeSexpr;
> virBufferEscapeShell;
> virBufferEscapeString;
> diff --git a/src/util/virbuffer.c b/src/util/virbuffer.c
> index d582e7dbec..ad6b29951e 100644
> --- a/src/util/virbuffer.c
> +++ b/src/util/virbuffer.c
> @@ -33,6 +33,7 @@
> #include "virbuffer.h"
> #include "viralloc.h"
> #include "virerror.h"
> +#include "virstring.h"
>
>
> /* If adding more fields, ensure to edit buf.h to match
> @@ -588,6 +589,109 @@ virBufferEscape(virBufferPtr buf, char escape, const char
*toescape,
> VIR_FREE(escaped);
> }
>
> +
> +struct _virBufferEscapePair {
> + char escape;
> + char *toescape;
> +};
> +
> +
> +/**
> + * virBufferEscapeN:
> + * @buf: the buffer to append to
> + * @format: a printf like format string but with only one %s parameter
> + * @str: the string argument which needs to be escaped
> + * @...: the variable list of arguments composed
> + *
> + * The variable list of arguments @... must be composed of
> + * 'char escape, char *toescape' pairs followed by NULL.
So most of the complexity you have here is to deal with the ability
to turn a single character into a string of escaped characters. Unless
I'm missing something, you don't actually use that ability in practice.
If we make it more restrictive so you just have a 1-1 mapping we can
simplify the API & implementation. eg
virBufferEscapeN(virBufferPtr buf,
const char *format,
const char *str,
const char *forbidden,
const char *replacements)
with strlen(forbidden) == strlen(replacements);
The idea was that a group of characters can be escaped with one character,
so far the usage seems to be really simple. Currently this would work and
it would be really simple:
virBufferEscapeN(buf, "%s", str, ",=", ",\\");
but imagine this scenario:
virBufferEscapeN(buf, "%s", str, ",=%&*()",
",\\\\\\\\\\\\");
virBufferEscapeN(buf, "%s", str, ',', ",", '\\',
"=%&*()", NULL);
I think that the second approach is better and easier for user of
virBufferEscapeN.
> + *
> + * This has the same functionality as virBufferEscape with the extension
> + * that allows to specify multiple pairs of chars that needs to be escaped.
> + */
> +void
> +virBufferEscapeN(virBufferPtr buf,
> + const char *format,
> + const char *str,
> + ...)
> +{
> + int len;
> + size_t i;
> + char escape;
> + char *toescape;
> + char *toescapeall = NULL;
> + char *escaped = NULL;
> + char *out;
> + const char *cur;
> + struct _virBufferEscapePair escapeItem;
> + struct _virBufferEscapePair *escapeList = NULL;
> + size_t nescapeList = 0;
> + va_list ap;
> +
> + if ((format == NULL) || (buf == NULL) || (str == NULL))
> + return;
> +
> + if (buf->error)
> + return;
> +
> + va_start(ap, str);
> +
> + while ((escape = va_arg(ap, int))) {
> + if (!(toescape = va_arg(ap, char *))) {
> + virBufferSetError(buf, errno);
> + goto cleanup;
> + }
> +
> + escapeItem.escape = escape;
> + escapeItem.toescape = toescape;
> +
> + if (VIR_STRCAT_QUIET(toescapeall, toescape) < 0) {
> + virBufferSetError(buf, errno);
> + goto cleanup;
> + }
> +
> + if (VIR_APPEND_ELEMENT_QUIET(escapeList, nescapeList, escapeItem) < 0)
{
> + virBufferSetError(buf, errno);
> + goto cleanup;
> + }
> + }
This whole loop would go away with the simpler API contract, which
nicely avoids doing allocations in the loop body.
> + len = strlen(str);
> + if (strcspn(str, toescapeall) == len) {
> + virBufferAsprintf(buf, format, str);
> + goto cleanup;
> + }
> +
> + if (xalloc_oversized(2, len) ||
> + VIR_ALLOC_N_QUIET(escaped, 2 * len + 1) < 0) {
> + virBufferSetError(buf, errno);
> + goto cleanup;
> + }
> +
> + cur = str;
> + out = escaped;
> + while (*cur != 0) {
> + for (i = 0; i < nescapeList; i++) {
> + if (strchr(escapeList[i].toescape, *cur)) {
> + *out++ = escapeList[i].escape;
> + break;
> + }
> + }
> + *out++ = *cur;
> + cur++;
> + }
> + *out = 0;
> +
> + virBufferAsprintf(buf, format, escaped);
> +
> + cleanup:
> + va_end(ap);
> + VIR_FREE(toescapeall);
> + VIR_FREE(escapeList);
> + VIR_FREE(escaped);
> +}
Regards,
Daniel
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