Re: [libvirt] [PATCH v3 02/14] util: Implement virStringFilterLines()

[John Ferlan]

On 05/04/2018 04:21 PM, Stefan Berger wrote:
> Implement virStringFilterLines() that takes as an input a buffer with text
> and extracts each line that contains a given needle. The size of each re-
> turned line can be restricted and if it is restricted '...' will automa-
> tically be appended.
> 
> Signed-off-by: Stefan Berger 
> ---
>  src/util/virstring.c | 62 
> 
>  src/util/virstring.h |  3 +++
>  2 files changed, 65 insertions(+)
> 

? No src/libvirt_private.syms change to add the new function?

> diff --git a/src/util/virstring.c b/src/util/virstring.c
> index 15f367a..f1d91c7 100644
> --- a/src/util/virstring.c
> +++ b/src/util/virstring.c
> @@ -1499,3 +1499,65 @@ virStringParsePort(const char *str,
>  
>  return 0;
>  }

Similar to 1/14 - 2 blank lines...

> +
> +/**
> + * virStringFilterLines:

I think this is more ExtractLines

as compared to virStringFilterChars which filters out certain chars from
a buffer and returns a buffer with those filtered out.

> + * @input: input buffer with text
> + * @needle: the needle to search in each line
> + * @maxlinelen: maximum line length of each line in output buffer;
> + *  0 to not restrict
> + *
> + * Search for a given needle in each line of the input buffer and create
> + * an output buffer that contains only these line.

Seems to be an incomplete thought, but I can adjust. So given Extract
vs. Filter:

 * Search for a given @needle in each line of the @input buffer and
 * create a return buffer that contains only those lines with the
 * @needle. Each output buffer line can be further restricted by
 * providing @maxlinelen in which case the output line would be
 * truncated @maxlinelen with "..." appended to the line to indicate
 * the truncation.
 *
 * Returns NULL on failure or a buffer with the extracted lines. It
 * is up to the caller to free the returned buffer.

> + */
> +char *
> +virStringFilterLines(char *input, const char *needle, size_t maxlinelen)

... and 1 line per argument.


> +{
> +char *sol = input;
> +char *eol;
> +char *buf = NULL;
> +size_t buflen = 1, llen;
> +const char *dots = "...";
> +

See below [1]

+if (!input || !needle) {
+virReportError(VIR_ERR_INALID_ARG,
+   _("neither input=%s nor needle=%s can be NULL"),
+   NULLSTR(input), NULLSTR(needle));
+return NULL;
+}
+

> +while (*sol) {
> +eol = strchr(sol, '\n');
> +if (eol)
> +*eol = 0;
> +
> +if (strstr(sol, needle)) {
> +size_t additional = 0;
> +
> +llen = strlen(sol);
> +if (maxlinelen && llen > maxlinelen) {
> +llen = maxlinelen;
> +additional = strlen(dots);
> +}
> +
> +if (VIR_REALLOC_N(buf, buflen + llen + additional + 1) < 0) {
> +VIR_FREE(buf);
> +if (*eol)

Ran the patch through Coverity and it complained right here... I think
you meant "if (eol)", right?

> +*eol = '\n';
> +return NULL;
> +}
> +strncpy([buflen - 1], sol, llen);
> +buflen += llen;
> +
> +if (additional) {
> +strncpy([buflen - 1], dots, additional);
> +buflen += additional;
> +}
> +
> +strcpy([buflen - 1], "\n");
> +buflen += 1;
> +}
> +
> +if (eol)
> +*eol = '\n';
> +else
> +break;
> +
> +sol = eol + 1;
> +}
> +
> +return buf;
> +}
> diff --git a/src/util/virstring.h b/src/util/virstring.h
> index fa2ec1d..1fb9851 100644
> --- a/src/util/virstring.h
> +++ b/src/util/virstring.h
> @@ -309,4 +309,7 @@ int virStringParsePort(const char *str,
> unsigned int *port)
>  ATTRIBUTE_NONNULL(2) ATTRIBUTE_RETURN_CHECK;
>  
> +char *virStringFilterLines(char *input, const char *needle, size_t 
> maxlinelen)
> +ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2);

[1]
Unfortunately all this does is ensure no one calls this with (NULL,
NULL,...)... In practice, if @input or @needle is assigned to NULL, the
compiler won't catch it.


With the adjustments,

Reviewed-by: John Ferlan 

But like patch 1, I do have some other concerns later in patch 7 when
this is used.

John

> +
>  #endif /* __VIR_STRING_H__ */
> 

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[libvirt] [PATCH v3 02/14] util: Implement virStringFilterLines()

[Stefan Berger]

Implement virStringFilterLines() that takes as an input a buffer with text
and extracts each line that contains a given needle. The size of each re-
turned line can be restricted and if it is restricted '...' will automa-
tically be appended.

Signed-off-by: Stefan Berger 
---
 src/util/virstring.c | 62 
 src/util/virstring.h |  3 +++
 2 files changed, 65 insertions(+)

diff --git a/src/util/virstring.c b/src/util/virstring.c
index 15f367a..f1d91c7 100644
--- a/src/util/virstring.c
+++ b/src/util/virstring.c
@@ -1499,3 +1499,65 @@ virStringParsePort(const char *str,
 
 return 0;
 }
+
+/**
+ * virStringFilterLines:
+ * @input: input buffer with text
+ * @needle: the needle to search in each line
+ * @maxlinelen: maximum line length of each line in output buffer;
+ *  0 to not restrict
+ *
+ * Search for a given needle in each line of the input buffer and create
+ * an output buffer that contains only these line.
+ */
+char *
+virStringFilterLines(char *input, const char *needle, size_t maxlinelen)
+{
+char *sol = input;
+char *eol;
+char *buf = NULL;
+size_t buflen = 1, llen;
+const char *dots = "...";
+
+while (*sol) {
+eol = strchr(sol, '\n');
+if (eol)
+*eol = 0;
+
+if (strstr(sol, needle)) {
+size_t additional = 0;
+
+llen = strlen(sol);
+if (maxlinelen && llen > maxlinelen) {
+llen = maxlinelen;
+additional = strlen(dots);
+}
+
+if (VIR_REALLOC_N(buf, buflen + llen + additional + 1) < 0) {
+VIR_FREE(buf);
+if (*eol)
+*eol = '\n';
+return NULL;
+}
+strncpy([buflen - 1], sol, llen);
+buflen += llen;
+
+if (additional) {
+strncpy([buflen - 1], dots, additional);
+buflen += additional;
+}
+
+strcpy([buflen - 1], "\n");
+buflen += 1;
+}
+
+if (eol)
+*eol = '\n';
+else
+break;
+
+sol = eol + 1;
+}
+
+return buf;
+}
diff --git a/src/util/virstring.h b/src/util/virstring.h
index fa2ec1d..1fb9851 100644
--- a/src/util/virstring.h
+++ b/src/util/virstring.h
@@ -309,4 +309,7 @@ int virStringParsePort(const char *str,
unsigned int *port)
 ATTRIBUTE_NONNULL(2) ATTRIBUTE_RETURN_CHECK;
 
+char *virStringFilterLines(char *input, const char *needle, size_t maxlinelen)
+ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2);
+
 #endif /* __VIR_STRING_H__ */
-- 
2.5.5

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