On 09/30/2011 12:22 AM, 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(-)
diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
index c2a3fab..695ff33 100644
--- a/src/libvirt_private.syms
+++ b/src/libvirt_private.syms
@@ -22,12 +22,14 @@ virBitmapString;
# buf.h
virBufferAdd;
virBufferAddChar;
+virBufferAdjustIndent;
virBufferAsprintf;
virBufferContentAndReset;
virBufferError;
virBufferEscapeSexpr;
virBufferEscapeString;
virBufferFreeAndReset;
+virBufferGetIndent;
virBufferStrcat;
virBufferURIEncodeString;
virBufferUse;
diff --git a/src/util/buf.c b/src/util/buf.c
index 98bb681..b409de4 100644
--- a/src/util/buf.c
+++ b/src/util/buf.c
@@ -28,6 +28,7 @@ struct _virBuffer {
unsigned int size;
unsigned int use;
unsigned int error; /* errno value, or -1 for usage error */
+ int indent;
char *content;
};
@@ -44,10 +45,54 @@ virBufferSetError(virBufferPtr buf, int error)
VIR_FREE(buf->content);
buf->size = 0;
buf->use = 0;
+ buf->indent = 0;
buf->error = error;
}
/**
+ * virBufferAdjustIndent:
+ * @buf: the buffer
+ * @indent: adjustment to make
+ *
+ * Alter the auto-indent value by adding indent (positive to increase,
+ * negative to decrease). Automatic indentation is performed by all
+ * additive functions when the existing buffer is empty or ends with a
+ * newline (however, note that no indentation is added if you append a
+ * string with an embedded newline). If @indent would cause overflow,
+ * the buffer error indicator is set.
+ */
+void
+virBufferAdjustIndent(virBufferPtr buf, int indent)
+{
+ if (!buf || buf->error)
+ return;
+ if (indent> 0 ? INT_MAX - indent< buf->indent
The priority of operators is all right here, yet maybe parentheses
around the expression (INT_MAX - indent) will make this more obviously?.
Just saying, never mind.
+ : buf->indent< -indent) {
+ virBufferSetError(buf, -1);
+ return;
+ }
+ buf->indent += indent;
+}
+
+/**
+ * virBufferGetIndent:
+ * @buf: the buffer
+ * @dynamic: if false, return set value; if true, return 0 unless next
+ * append would be affected by auto-indent
+ *
+ * Return the current auto-indent value, or -1 if there has been an error.
+ */
+int
+virBufferGetIndent(const virBufferPtr buf, bool dynamic)
+{
+ if (!buf || buf->error)
+ return -1;
+ if (dynamic&& buf->use&& buf->content[buf->use - 1] != '\n')
+ return 0;
+ return buf->indent;
+}
+
+/**
* virBufferGrow:
* @buf: the buffer
* @len: the minimum free size to allocate on top of existing used space
@@ -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;
- 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);
}
/**
@@ -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);
+
if (buf->size == 0&&
virBufferGrow(buf, 100)< 0)
return;
@@ -287,10 +325,12 @@ virBufferVasprintf(virBufferPtr buf, const char *format,
va_list argptr)
* virBufferEscapeString:
* @buf: the buffer to append to
* @format: a printf like format string but with only one %s parameter
- * @str: the string argument which need to be escaped
+ * @str: the string argument which needs to be escaped
*
- * Do a formatted print with a single string to an XML buffer. The string
- * is escaped to avoid generating a not well-formed XML instance.
+ * Do a formatted print with a single string to an XML buffer. The
+ * string is escaped for use in XML. If @str is NULL, nothing is
+ * added (not even the rest of @format). Auto indentation may be
+ * applied.
*/
void
virBufferEscapeString(virBufferPtr buf, const char *format, const char *str)
@@ -372,11 +412,12 @@ virBufferEscapeString(virBufferPtr buf, const char
*format, const char *str)
* virBufferEscapeSexpr:
* @buf: the buffer to append to
* @format: a printf like format string but with only one %s parameter
- * @str: the string argument which need to be escaped
+ * @str: the string argument which needs to be escaped
*
- * Do a formatted print with a single string to an sexpr buffer. The string
- * is escaped to avoid generating a sexpr that xen will choke on. This
- * doesn't fully escape the sexpr, just enough for our code to work.
+ * Do a formatted print with a single string to an sexpr buffer. The
+ * string is escaped to avoid generating a sexpr that xen will choke
+ * on. This doesn't fully escape the sexpr, just enough for our code
+ * to work. Auto indentation may be applied.
*/
void
virBufferEscapeSexpr(virBufferPtr buf,
@@ -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);
+
for (p = str; *p; ++p) {
if (c_isalnum(*p))
grow_size++;
@@ -454,7 +498,7 @@ virBufferURIEncodeString(virBufferPtr buf, const char *str)
grow_size += 3; /* %ab */
}
- if (virBufferGrow (buf, grow_size)< 0)
+ if (virBufferGrow(buf, grow_size)< 0)
return;
for (p = str; *p; ++p) {
@@ -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);
}
diff --git a/src/util/buf.h b/src/util/buf.h
index 42a5044..08cb727 100644
--- a/src/util/buf.h
+++ b/src/util/buf.h
@@ -24,15 +24,16 @@ typedef struct _virBuffer virBuffer;
typedef virBuffer *virBufferPtr;
# ifndef __VIR_BUFFER_C__
-# define VIR_BUFFER_INITIALIZER { 0, 0, 0, NULL }
+# define VIR_BUFFER_INITIALIZER { 0, 0, 0, 0, NULL }
-/* This struct must be kept in syn with the real struct
+/* This struct must be kept in sync with the real struct
in the buf.c impl file */
struct _virBuffer {
unsigned int a;
unsigned int b;
unsigned int c;
- char *d;
+ int d;
+ char *e;
};
# endif
@@ -55,6 +56,9 @@ void virBufferEscapeSexpr(virBufferPtr buf, const char
*format,
void virBufferURIEncodeString(virBufferPtr buf, const char *str);
# define virBufferAddLit(buf_, literal_string_) \
- virBufferAdd (buf_, "" literal_string_ "", sizeof literal_string_ - 1)
+ virBufferAdd(buf_, "" literal_string_ "", sizeof literal_string_ - 1)
+
+void virBufferAdjustIndent(virBufferPtr buf, int indent);
+int virBufferGetIndent(const virBufferPtr buf, bool dynamic);
#endif /* __VIR_BUFFER_H__ */
diff --git a/tests/virbuftest.c b/tests/virbuftest.c
index 01db313..2f94e1c 100644
--- a/tests/virbuftest.c
+++ b/tests/virbuftest.c
@@ -20,7 +20,7 @@ struct testInfo {
int doEscape;
};
-static int testBufInfiniteLoop(const void *data ATTRIBUTE_UNUSED)
+static int testBufInfiniteLoop(const void *data)
{
virBuffer bufinit = VIR_BUFFER_INITIALIZER;
virBufferPtr buf =&bufinit;
@@ -28,18 +28,13 @@ static int testBufInfiniteLoop(const void *data
ATTRIBUTE_UNUSED)
int ret = -1;
const struct testInfo *info = data;
- /* This relies of virBuffer internals, so may break if things change
- * in the future */
virBufferAddChar(buf, 'a');
- if (buf->a != 1002 || buf->b != 1) {
- TEST_ERROR("Buf was not expected size, size=%d use=%d\n",
- buf->a, buf->b);
- goto out;
- }
/*
- * Infinite loop triggers if:
+ * Infinite loop used to trigger if:
* (strlen + 1> 1000)&& (strlen == buf-size - buf-use - 1)
+ * which was the case after the above addchar at the time of the bug.
+ * This test is a bit fragile, since it relies on virBuffer internals.
*/
if (virAsprintf(&addstr, "%*s", buf->a - buf->b - 1, "a")< 0) {
goto out;
@@ -63,6 +58,77 @@ out:
return ret;
}
+static int testBufAutoIndent(const void *data ATTRIBUTE_UNUSED)
+{
+ virBuffer bufinit = VIR_BUFFER_INITIALIZER;
+ virBufferPtr buf =&bufinit;
+ const char expected[] =
+ " 1\n 2\n 3\n 4\n 5\n 6\n 7\n&\n 8\n 9\n";
+ char *result = NULL;
+ int ret = 0;
+
+ if (virBufferGetIndent(buf, false) != 0 ||
+ virBufferGetIndent(buf, true) != 0) {
+ TEST_ERROR("Wrong indentation");
+ ret = -1;
+ }
+ virBufferAdjustIndent(buf, 3);
+ if (virBufferGetIndent(buf, false) != 3 ||
+ virBufferGetIndent(buf, true) != 3 ||
+ virBufferError(buf)) {
+ TEST_ERROR("Wrong indentation");
+ ret = -1;
+ }
+ virBufferAdjustIndent(buf, -2);
+ if (virBufferGetIndent(buf, false) != 1 ||
+ virBufferGetIndent(buf, true) != 1 ||
+ virBufferError(buf)) {
+ TEST_ERROR("Wrong indentation");
+ ret = -1;
+ }
So now buf->indent is 1. Go to the next step, the indent is given -2
again, see what will happen.
if virBufferAdjustIndent failed to check the indent overflow, the
buf->indent will be -1,too, so it may avoid the check
(virBufferGetIndent(buf, false) != -1) and (virBufferGetIndent(buf,
true) != -1).
+ virBufferAdjustIndent(buf, -2);
So I think -3 may be better.
+ if (virBufferGetIndent(buf, false) != -1 ||
+ virBufferGetIndent(buf, true) != -1 ||
+ virBufferError(buf) != -1) {
+ TEST_ERROR("Usage error not flagged");
+ ret = -1;
+ }
+ virBufferFreeAndReset(buf);
+ if (virBufferGetIndent(buf, false) != 0 ||
+ virBufferGetIndent(buf, true) != 0 ||
+ virBufferError(buf)) {
+ TEST_ERROR("Reset didn't clear indentation");
+ ret = -1;
+ }
+ virBufferAdjustIndent(buf, 2);
+ virBufferAddLit(buf, "1");
+ if (virBufferGetIndent(buf, false) != 2 ||
+ virBufferGetIndent(buf, true) != 0) {
+ TEST_ERROR("Wrong indentation");
+ ret = -1;
+ }
+ virBufferAddLit(buf, "\n");
+ virBufferAdd(buf, "" "2\n", -1); /* Extra "" appeases syntax-check */
+ virBufferAddChar(buf, '3');
+ virBufferAddChar(buf, '\n');
+ virBufferAsprintf(buf, "%d", 4);
+ virBufferAsprintf(buf, "%c", '\n');
+ virBufferStrcat(buf, "5", "\n", "6\n", NULL);
+ virBufferEscapeString(buf, "%s\n", "7");
+ virBufferEscapeString(buf, "%s\n", "&");
+ virBufferEscapeSexpr(buf, "%s", "8\n");
+ virBufferURIEncodeString(buf, "9");
+ virBufferAddChar(buf, '\n');
+
+ result = virBufferContentAndReset(buf);
+ if (!result || STRNEQ(result, expected)) {
+ virtTestDifference(stderr, expected, result);
+ ret = -1;
+ }
+ VIR_FREE(result);
+ return ret;
+}
+
static int
mymain(void)
{
@@ -78,6 +144,7 @@ mymain(void)
DO_TEST("EscapeString infinite loop", testBufInfiniteLoop, 1);
DO_TEST("VSprintf infinite loop", testBufInfiniteLoop, 0);
+ DO_TEST("Auto-indentation", testBufAutoIndent, 0);
return(ret==0 ? EXIT_SUCCESS : EXIT_FAILURE);
}
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