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New helper functions with printf/scanf format specifiers #183

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127 changes: 36 additions & 91 deletions apteryx.c
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Original file line number Diff line number Diff line change
Expand Up @@ -502,62 +502,37 @@ apteryx_set (const char *path, const char *value)
}

bool
apteryx_cas_string (const char *path, const char *key, const char *value, uint64_t ts)
_apteryx_casf (uint64_t ts, const char *format, va_list vl)
{
char *full_path;
size_t len;
bool res = false;

/* Create full path */
if (key)
len = asprintf (&full_path, "%s/%s", path, key);
else
len = asprintf (&full_path, "%s", path);
if (len)
{
res = apteryx_cas (full_path, value, ts);
free (full_path);
}
if (!format)
return false;
char *path = g_strdup_vprintf (format, vl);
char *value = va_arg (vl, char *);
value = value ? g_strdup_vprintf (value, vl) : NULL;
bool res = apteryx_cas (path, value, ts);
g_free (value);
g_free (path);
return res;
}

bool
apteryx_set_string (const char *path, const char *key, const char *value)
{
return apteryx_cas_string (path, key, value, UINT64_MAX);
}

bool
apteryx_cas_int (const char *path, const char *key, int32_t value, uint64_t ts)
apteryx_casf (uint64_t ts, const char *format, ...)
{
char *full_path;
size_t len;
char *v;
bool res = false;

/* Create full path */
if (key)
len = asprintf (&full_path, "%s/%s", path, key);
else
len = asprintf (&full_path, "%s", path);
if (len)
{
/* Store as a string at the moment */
len = asprintf ((char **) &v, "%d", value);
if (len)
{
res = apteryx_cas (full_path, v, ts);
free ((void *) v);
}
free (full_path);
}
va_list vl;
va_start (vl, format);
bool res = _apteryx_casf (ts, format, vl);
va_end (vl);
return res;
}

bool
apteryx_set_int (const char *path, const char *key, int32_t value)
apteryx_setf (const char *format, ...)
{
return apteryx_cas_int (path, key, value, UINT64_MAX);
va_list vl;
va_start (vl, format);
bool res = _apteryx_casf (UINT64_MAX, format, vl);
va_end (vl);
return res;
}

typedef struct _get_data_t
Expand Down Expand Up @@ -636,53 +611,23 @@ apteryx_get (const char *path)
return value;
}

char *
apteryx_get_string (const char *path, const char *key)
{
char *full_path;
size_t len;
char *value = NULL;
char *str = NULL;

/* Create full path */
if (key)
len = asprintf (&full_path, "%s/%s", path, key);
else
len = asprintf (&full_path, "%s", path);
if (len)
{
if ((value = apteryx_get ((const char *) full_path)))
{
str = (char *) value;
}
free (full_path);
}
return str;
}

int32_t
apteryx_get_int (const char *path, const char *key)
int
apteryx_getf (const char *format, ...)
{
char *full_path;
size_t len;
char *v = NULL;
int value = -1;

/* Create full path */
if (key)
len = asprintf (&full_path, "%s/%s", path, key);
else
len = asprintf (&full_path, "%s", path);
if (len)
{
if ((v = apteryx_get (full_path)))
{
value = atoi ((char *) v);
free (v);
}
free (full_path);
}
return value;
va_list vl;
if (!format)
return 0;
va_start (vl, format);
char *path = g_strdup_vprintf (format, vl);
char *value = apteryx_get (path);
free (path);
if (!value)
return 0;
format = va_arg (vl, char *);
int res = vsscanf (value, format, vl);
free (value);
va_end (vl);
return res;
}

GNode *
Expand Down
116 changes: 86 additions & 30 deletions apteryx.h
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Original file line number Diff line number Diff line change
Expand Up @@ -37,6 +37,7 @@
#include <stdio.h>
#include <stdbool.h>
#include <stdint.h>
#include <string.h>
#include <glib.h>

/** Apteryx configuration
Expand Down Expand Up @@ -149,10 +150,28 @@ bool apteryx_dump (const char *path, FILE *fp);
* @return false if the path is invalid
*/
bool apteryx_set (const char *path, const char *value);
/** Helper to extend the path with the specified key */
bool apteryx_set_string (const char *path, const char *key, const char *value);
/** Helper to store a simple int at an extended path */
bool apteryx_set_int (const char *path, const char *key, int32_t value);

/**
* Set a path/value using standard printf format specifiers
* Example:
apteryx_setf ("/rules/%d/index", index, "%d", index);
apteryx_setf ("/rules/%d/name", index, "%s", name);
apteryx_setf ("/rules/%d/action", index, "%d", action);
* @param format variable list of path and value format specifiers
* @return true on a successful set
* @return false if the path is invalid or the path/value cannot be formatted
*/
bool apteryx_setf (const char *format, ...);

/** Deprecated helpers */
static inline bool apteryx_set_string (const char *path, const char *key, const char *value)
{
return apteryx_setf ("%s%s%s", path, key ? "/" : "", key ? : "", value);
}
static inline bool apteryx_set_int (const char *path, const char *key, int32_t value)
{
return apteryx_setf ("%s%s%s", path, key ? "/" : "", key ? : "", "%d", value);
}

/**
* Get a path/value from Apteryx
Expand All @@ -161,10 +180,33 @@ bool apteryx_set_int (const char *path, const char *key, int32_t value);
* @return NULL if the path is invalid
*/
char *apteryx_get (const char *path);
/** Helper to retrieve the value using an extended path based on the specified key */
char *apteryx_get_string (const char *path, const char *key);
/** Helper to retrieve a simple integer from an extended path */
int32_t apteryx_get_int (const char *path, const char *key);

/**
* Get a path/value using standard scanf format specifiers
* Example:
apteryx_getf ("/rules/%d/name", index, "%15s", name);
apteryx_getf ("/rules/%d/description", index, "%31[^\\0]", description);
apteryx_getf ("/rules/%d/action", index, "%d", &action);
* @param format variable list of path and value format specifiers
* @return number of successfully parsed items (0 if path value is NULL)
*/
int apteryx_getf (const char *format, ...);

/** Deprecated helpers */
static inline char *apteryx_get_string (const char *path, const char *key)
{
char _v[8192] = {};
if (apteryx_getf ("%s%s%s", path, key ? "/" : "", key ? : "", "%8191[^\\0]", _v))
return strdup(_v);
return NULL;
}
static inline int32_t apteryx_get_int (const char *path, const char *key)
{
int32_t _v = -1;
if (apteryx_getf ("%s%s%s", path, key ? "/" : "", key ?: "", "%d", &_v))
return _v;
return -1;
}

/**
* Get the last change timestamp of a given path
Expand All @@ -177,42 +219,56 @@ uint64_t apteryx_timestamp (const char *path);
* Set a path/value in Apteryx, but only if the existing
* value has not changed since the specified timestamp.
* Can be used for a Compare-And-Swap operation.
* Example: Set a value only if has not changed since read
uint64_t ts = apteryx_timestamp ("/interfaces/eth0/state");
char *state = apteryx_get ("/interfaces/eth0/state");
if (strcmp (state, "up") == 0 &&
apteryx_cas (ts, "/interfaces/eth0/state", "down"))
return true;
return false;
* @param path path to the value to set
* @param value value to set at the specified path
* @param ts timestamp to be compared to the paths last change time
* @return true on a successful set
* @return false if the set failed (errno == -EBUSY if timestamp comparison failed)
*/
bool apteryx_cas (const char *path, const char *value, uint64_t ts);

/**
* Set a path/value using standard printf format specifiers,
* but only if the existing value has not changed since
* the specified timestamp.
* Example: Safely reserve the next free row in a table
uint32_t index = 1;
while (index > 0) {
if (apteryx_cas_int (path, key, index, 0))
if (apteryx_casf (0, "/rules/%d/index", index))
break;
index++;
}
* Example: Safely updating a 32-bit bitmap
while (1) {
uint64_t ts = apteryx_timestamp (path);
uint32_t bitmap = 0;
char *value = apteryx_get (path);
if (value)
{
sscanf (value, "%"PRIx32, &bitmap);
free (value);
}
uint32_t bitmap = apteryx_getf (path, "%"PRIx32, &bitmap) ? bitmap : 0;
bitmap = (bitmap & ~clear) | set;
if (asprintf (&value, "%"PRIx32, bitmap) > 0) {
bool success = apteryx_cas (path, value, ts);
free (value);
if (success || errno != -EBUSY)
return success;
}
if (apteryx_casf (ts, "%"PRIx32, bitmap))
return;
}
* @param path path to the value to set
* @param value value to set at the specified path
* @param ts timestamp to be compared to the paths last change time
* @param format variable list of path and value format specifiers
* @return true on a successful set
* @return false if the set failed (errno == -EBUSY if timestamp comparison failed)
* @return false if the path is invalid or the path/value cannot be formatted
*/
bool apteryx_cas (const char *path, const char *value, uint64_t ts);
/** Helper to extend the path with the specified key */
bool apteryx_cas_string (const char *path, const char *key, const char *value, uint64_t ts);
/** Helper to store a simple int at an extended path */
bool apteryx_cas_int (const char *path, const char *key, int32_t value, uint64_t ts);
bool apteryx_casf (uint64_t ts, const char *format, ...);

/** Deprecated helpers */
static inline bool apteryx_cas_string (const char *path, const char *key, const char *value, uint64_t ts)
{
return apteryx_casf (ts, "%s%s%s", path, key ? "/" : "", key ? : "", value);
}
static inline bool apteryx_cas_int (const char *path, const char *key, int32_t value, uint64_t ts)
{
return apteryx_casf (ts, "%s%s%s", path, key ? "/" : "", key ? : "", "%d", value);
}

/**
* Helpers for generating and parsing an Apteryx tree.
Expand Down
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