[libvirt] [PATCHv2 04/13] virbuf: add auto-indentation support
Peter Krempa
pkrempa at redhat.com
Wed Oct 19 17:51:46 UTC 2011
On 09/29/2011 06:22 PM, Eric Blake wrote:
> Rather than having to adjust all callers in a chain to deal with
> indentation, it is nicer to have virBuffer do auto-indentation.
>
> * src/util/buf.h (_virBuffer): Increase size.
> (virBufferAdjustIndent, virBufferGetIndent): New prototypes.
> * src/libvirt_private.syms (buf.h): Export new functions.
> * src/util/buf.c (virBufferAdjustIndent, virBufferGetIndent): New
> functions.
> (virBufferSetError, virBufferAdd, virBufferAddChar)
> (virBufferVasprintf, virBufferStrcat, virBufferURIEncodeString):
> Implement auto-indentation.
> * tests/virbuftest.c (testBufAutoIndent): Test it.
> (testBufInfiniteLoop): Don't rely on internals.
> Idea by Daniel P. Berrange.
> ---
> src/libvirt_private.syms | 2 +
> src/util/buf.c | 138 ++++++++++++++++++++++++++++-----------------
> src/util/buf.h | 12 +++-
> tests/virbuftest.c | 85 +++++++++++++++++++++++++---
> 4 files changed, 172 insertions(+), 65 deletions(-)
>
> @@ -79,35 +124,39 @@ virBufferGrow(virBufferPtr buf, unsigned int len)
>
> /**
> * virBufferAdd:
> - * @buf: the buffer to add to
> - * @str: the string
> - * @len: the number of bytes to add
> + * @buf: the buffer to append to
> + * @str: the string
> + * @len: the number of bytes to add, or -1
> *
> - * Add a string range to an XML buffer. if len == -1, the length of
> - * str is recomputed to the full string.
> + * Add a string range to an XML buffer. If @len == -1, the length of
> + * str is recomputed to the full string. Auto indentation may be applied.
> *
> */
> void
> virBufferAdd(const virBufferPtr buf, const char *str, int len)
> {
> unsigned int needSize;
> + int indent;
/* context for a later comment */
> - if ((str == NULL) || (buf == NULL) || (len == 0))
> + if (!str || !buf || (len == 0&& buf->indent == 0))
> return;
>
> if (buf->error)
> return;
>
> + indent = virBufferGetIndent(buf, true);
> +
> if (len< 0)
> len = strlen(str);
>
> - needSize = buf->use + len + 2;
> + needSize = buf->use + indent + len + 2;
> if (needSize> buf->size&&
> virBufferGrow(buf, needSize - buf->use)< 0)
> return;
>
> - memcpy (&buf->content[buf->use], str, len);
> - buf->use += len;
> + memset(&buf->content[buf->use], ' ', indent);
> + memcpy(&buf->content[buf->use + indent], str, len);
> + buf->use += indent + len;
> buf->content[buf->use] = '\0';
> }
>
> @@ -116,27 +165,13 @@ virBufferAdd(const virBufferPtr buf, const char *str, int len)
> * @buf: the buffer to append to
> * @c: the character to add
> *
> - * Add a single character 'c' to a buffer.
> + * Add a single character 'c' to a buffer. Auto indentation may be applied.
> *
> */
> void
> -virBufferAddChar (virBufferPtr buf, char c)
> +virBufferAddChar(virBufferPtr buf, char c)
> {
> - unsigned int needSize;
> -
> - if (buf == NULL)
> - return;
> -
> - if (buf->error)
> - return;
> -
> - needSize = buf->use + 2;
> - if (needSize> buf->size&&
> - virBufferGrow (buf, needSize - buf->use)< 0)
> - return;
> -
> - buf->content[buf->use++] = c;
> - buf->content[buf->use] = '\0';
> + virBufferAdd(buf,&c, 1);
> }
This has slightly more overhead than the previous version, but I don't
think adding a char is such a common operation that it would impact
performance. This also simplifies mantenance. I like it.
> /**
> @@ -218,7 +253,7 @@ virBufferUse(const virBufferPtr buf)
> * @format: the format
> * @...: the variable list of arguments
> *
> - * Do a formatted print to an XML buffer.
> + * Do a formatted print to an XML buffer. Auto indentation may be applied.
> */
> void
> virBufferAsprintf(virBufferPtr buf, const char *format, ...)
> @@ -231,11 +266,11 @@ virBufferAsprintf(virBufferPtr buf, const char *format, ...)
>
> /**
> * virBufferVasprintf:
> - * @buf: the buffer to dump
> + * @buf: the buffer to append to
> * @format: the format
> * @argptr: the variable list of arguments
> *
> - * Do a formatted print to an XML buffer.
> + * Do a formatted print to an XML buffer. Auto indentation may be applied.
> */
> void
> virBufferVasprintf(virBufferPtr buf, const char *format, va_list argptr)
> @@ -249,6 +284,9 @@ virBufferVasprintf(virBufferPtr buf, const char *format, va_list argptr)
> if (buf->error)
> return;
>
> + if (buf->indent)
> + virBufferAdd(buf, "", -1);
> +
virBufferAdd is a no-op, if this expression is true (see context above):
" if (!str || !buf || (len == 0 && buf->indent == 0))". You could save a
call to strlen and the if clause if you call virBufferAdd(buf, "", 0)
The len=0 will be automaticaly used (as the only way to accept len==0 as
a correct value is if indentation is requested). You can also save a
line with the if clause and call it directly. ( Looks like you've
prepared it for this to happen :D)
> if (buf->size == 0&&
> virBufferGrow(buf, 100)< 0)
> return;
> @@ -431,7 +472,7 @@ virBufferEscapeSexpr(virBufferPtr buf,
> *
> * Append the string to the buffer. The string will be URI-encoded
> * during the append (ie any non alpha-numeric characters are replaced
> - * with '%xx' hex sequences).
> + * with '%xx' hex sequences). Auto indentation may be applied.
> */
> void
> virBufferURIEncodeString(virBufferPtr buf, const char *str)
> @@ -447,6 +488,9 @@ virBufferURIEncodeString(virBufferPtr buf, const char *str)
> if (buf->error)
> return;
>
> + if (buf->indent)
> + virBufferAdd(buf, "", -1);
Same as above ...
> @@ -476,7 +520,8 @@ virBufferURIEncodeString(virBufferPtr buf, const char *str)
> * @buf: the buffer to append to
> * @...: the variable list of strings, the last argument must be NULL
> *
> - * Concatenate strings to an XML buffer.
> + * Concatenate strings to an XML buffer. Auto indentation may be applied
> + * after each string argument.
> */
> void
> virBufferStrcat(virBufferPtr buf, ...)
> @@ -488,18 +533,7 @@ virBufferStrcat(virBufferPtr buf, ...)
> return;
>
> va_start(ap, buf);
> -
> - while ((str = va_arg(ap, char *)) != NULL) {
> - unsigned int len = strlen(str);
> - unsigned int needSize = buf->use + len + 2;
> -
> - if (needSize> buf->size) {
> - if (virBufferGrow(buf, needSize - buf->use)< 0)
> - break;
> - }
> - memcpy(&buf->content[buf->use], str, len);
> - buf->use += len;
> - buf->content[buf->use] = 0;
> - }
> + while ((str = va_arg(ap, char *)) != NULL)
> + virBufferAdd(buf, str, -1);
> va_end(ap);
> }
Elegant.
> diff --git a/tests/virbuftest.c b/tests/virbuftest.c
>
The tests look fine to me and it's nice to have them.
ACK,
Peter
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