On Mon, 26 Oct 2009 21:57:27 +0100, Andre Prendel wrote:
> This patch cleans up function applyToFeature().
>
> Function applyToFeature() is nearly unreadable. There are some deep
> levels of indentation and cascades of loops makes code flow difficult to
> read.
>
> I split up this function into three smaller one. This reduces
> indentation levels and makes code flow clearer.
>
> Note:
> This is just the first step. I'm not happy with the mechanism. IMHO
> this generic way (function pointer) is not the best one. Hiding the
> compiler warnings (void (label)) in rrdGetSensors_DS() and
> rrdCGI_DEF() confirms my opinion.
>
> I think a more conrete way is a better approach. So this should be
> just the starting point for further optimizations.
>
> Changes v2:
>
> * Rename generate_features() to _appyToFeatures().
> * Get rid of needless variable num.
> * Change prototype of function pointer FeatureFN. None of the
> functions returns with an error, so we needn't a return value.
This would have been a nice little separate patch ;)
Some problems with this patch, see below:
>
> ---
>
> prog/sensord/rrd.c | 124 +++++++++++++++++++++++++++++------------------------
> 1 file changed, 70 insertions(+), 54 deletions(-)
> Index: sensors/prog/sensord/rrd.c
> ===================================================================
> --- sensors.orig/prog/sensord/rrd.c 2009-10-26 21:08:33.000000000 +0100
> +++ sensors/prog/sensord/rrd.c 2009-10-26 21:14:18.000000000 +0100
> @@ -68,7 +68,7 @@
> #define LOADAVG "loadavg"
> #define LOAD_AVERAGE "Load Average"
>
> -typedef int (*FeatureFN) (void *data, const char *rawLabel, const char *label,
> +typedef void (*FeatureFN) (void *data, const char *rawLabel, const char *label,
> const FeatureDescriptor *feature);
>
> static char rrdNextChar(char c)
> @@ -137,52 +137,72 @@
> }
> }
>
> -static int applyToFeatures(FeatureFN fn, void *data)
> +static int _applyToFeatures(FeatureFN fn, void *data,
> + const sensors_chip_name *chip,
> + const ChipDescriptor *desc)
> +{
> + int i;
> + const FeatureDescriptor *features = desc->features;
> + const FeatureDescriptor *feature;
> + const char *rawLabel;
> + char *label;
> +
> + for (i = 0; i < MAX_RRD_SENSORS && features[i].format; ++i) {
> + feature = features + i;
> + rawLabel = feature->feature->name;
> +
> + label = sensors_get_label(chip, feature->feature);
> + if (!label) {
> + sensorLog(LOG_ERR, "Error getting sensor label: %s/%s",
> + chip->prefix, rawLabel);
> + return -1;
> + }
> +
> + rrdCheckLabel(rawLabel, i);
> + fn(data, rrdLabels[i], label, feature);
> + free(label);
> + }
> + return 0;
> +}
> +
> +static ChipDescriptor *lookup_known_chips(const sensors_chip_name *chip)
> {
> - const sensors_chip_name *chip;
> - int i, j, ret = 0, num = 0;
> + int i;
>
> - for (j = 0; (ret == 0) && (j < sensord_args.numChipNames); ++ j) {
> - i = 0;
> - while ((ret == 0) && ((chip = sensors_get_detected_chips(&sensord_args.chipNames[j], &i)) != NULL)) {
> - int index0, chipindex = -1;
> -
> - /* Trick: we compare addresses here. We know it works
> - * because both pointers were returned by
> - * sensors_get_detected_chips(), so they refer to
> - * libsensors internal structures, which do not move.
> - */
> - for (index0 = 0; knownChips[index0].features; ++index0)
> - if (knownChips[index0].name == chip) {
> - chipindex = index0;
> - break;
> - }
> - if (chipindex >= 0) {
> - const ChipDescriptor *descriptor = &knownChips[chipindex];
> - const FeatureDescriptor *features = descriptor->features;
> -
> - for (index0 = 0; (ret == 0) && (num < MAX_RRD_SENSORS) && features[index0].format; ++index0) {
> - const FeatureDescriptor *feature = features + index0;
> - const char *rawLabel = feature->feature->name;
> - char *label = NULL;
> -
> - if (!(label = sensors_get_label(chip, feature->feature))) {
> - sensorLog(LOG_ERR, "Error getting sensor label: %s/%s", chip->prefix, rawLabel);
> - ret = -1;
> - } else {
> - rrdCheckLabel(rawLabel, num);
> - ret = fn(data,
> - rrdLabels[num],
> - label, feature);
> - ++ num;
> - }
> - if (label)
> - free(label);
> - }
> - }
> + /* Trick: we compare addresses here. We know it works
> + * because both pointers were returned by
> + * sensors_get_detected_chips(), so they refer to
> + * libsensors internal structures, which do not move.
> + */
> + for (i = 0; knownChips[i].features; i++) {
> + if (knownChips[i].name == chip) {
> + return &knownChips[i];
> }
> }
> - return ret;
> + return NULL;
> +}
> +
> +static int applyToFeatures(FeatureFN fn, void *data)
> +{
> + int i, i_detected, ret;
> + const sensors_chip_name *chip, *chip_arg;
> + ChipDescriptor *desc;
> +
> + for (i = 0; i < sensord_args.numChipNames; i++) {
> + chip_arg = &sensord_args.chipNames[i];
> + i_detected = 0;
> + while ((chip = sensors_get_detected_chips(chip_arg,
> + &i_detected))) {
> + desc = lookup_known_chips(chip);
> + if (!desc)
> + continue;
> +
> + ret = _applyToFeatures(fn, data, chip, desc);
> + if (ret)
> + return ret;
> + }
> + }
> + return 0;
> }
>
> struct ds {
> @@ -190,7 +210,7 @@
> const char **argv;
> };
>
> -static int rrdGetSensors_DS(void *_data, const char *rawLabel,
> +static void rrdGetSensors_DS(void *_data, const char *rawLabel,
> const char *label,
> const FeatureDescriptor *feature)
> {
> @@ -227,7 +247,6 @@
> sprintf(ptr, "DS:%s:GAUGE:%d:%s:%s", rawLabel, 5 *
> sensord_args.rrdTime, min, max);
> }
> - return 0;
> }
>
> static int rrdGetSensors(const char **argv)
> @@ -236,8 +255,8 @@
> struct ds data = { 0, argv};
> ret = applyToFeatures(rrdGetSensors_DS, &data);
> if (!ret && sensord_args.doLoad)
> - ret = rrdGetSensors_DS(&data, LOADAVG, LOAD_AVERAGE, NULL);
> - return ret ? -1 : data.num;
> + rrdGetSensors_DS(&data, LOADAVG, LOAD_AVERAGE, NULL);
> + return data.num;
This change doesn't seem to be required, nor desired. ret can still
hold an error value returned by applyToFeatures() and we want to
propagate it up to the caller.
> }
>
> int rrdInit(void)
> @@ -303,7 +322,7 @@
> int loadAvg;
> };
>
> -static int rrdCGI_DEF(void *_data, const char *rawLabel, const char *label,
> +static void rrdCGI_DEF(void *_data, const char *rawLabel, const char *label,
> const FeatureDescriptor *feature)
> {
> struct gr *data = _data;
> @@ -311,7 +330,6 @@
> if (!feature || (feature->rrd && (feature->type == data->type)))
> printf("\n\tDEF:%s=%s:%s:AVERAGE", rawLabel,
> sensord_args.rrdFile, rawLabel);
> - return 0;
> }
>
> /*
> @@ -339,14 +357,13 @@
> return color;
> }
>
> -static int rrdCGI_LINE(void *_data, const char *rawLabel, const char *label,
> +static void rrdCGI_LINE(void *_data, const char *rawLabel, const char *label,
> const FeatureDescriptor *feature)
> {
> struct gr *data = _data;
> if (!feature || (feature->rrd && (feature->type == data->type)))
> printf("\n\tLINE2:%s#%.6x:\"%s\"", rawLabel,
> rrdCGI_color(label), label);
> - return 0;
> }
>
> static struct gr graphs[] = {
> @@ -468,11 +485,10 @@
> if (!ret)
> ret = applyToFeatures(rrdCGI_DEF, graph);
> if (!ret && sensord_args.doLoad && graph->loadAvg)
> - ret = rrdCGI_DEF(graph, LOADAVG, LOAD_AVERAGE, NULL);
> - if (!ret)
> + rrdCGI_DEF(graph, LOADAVG, LOAD_AVERAGE, NULL);
> ret = applyToFeatures(rrdCGI_LINE, graph);
Messed up big time :p
> if (!ret && sensord_args.doLoad && graph->loadAvg)
> - ret = rrdCGI_LINE(graph, LOADAVG, LOAD_AVERAGE, NULL);
> + rrdCGI_LINE(graph, LOADAVG, LOAD_AVERAGE, NULL);
> printf (">\n</p>\n");
> }
> printf("<p>\n<small><b>sensord</b> by "
--
Jean Delvare
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