Planner: don't return static data in fake_dc()

fake_dc() used to return a statically allocated dc with statically
allocated samples. This is of course a questionable practice in
the light of multi-threading / resource ownership. Once these
problems were recognized, the parameter "alloc" was added. If set
to true, the function would still return a statically allocated
dc, but heap-allocated samples, which could then be copied in
a different dc.

All in all an ownership nightmare and a recipie for disaster.
The returned static dc was only used as a pointer to the samples
anyway. There are four callers of fake_dc() and they all have access
to a dc-structure without samples. Therefore, change the semantics
of fake_dc() to fill out the passed in dc. If the caller does
not care about the samples, it can simply reset the sample number
to zero after work.

Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>
This commit is contained in:
Berthold Stoeger 2018-05-05 19:26:48 +02:00 committed by Lubomir I. Ivanov
parent 450f0992a0
commit 920ff15f71
7 changed files with 39 additions and 40 deletions

View file

@ -109,33 +109,29 @@ static void fill_samples_no_avg(struct sample *s, int max_d, int max_t, double s
}
}
struct divecomputer *fake_dc(struct divecomputer *dc, bool alloc)
void fake_dc(struct divecomputer *dc)
{
static struct sample fake_samples[6];
static struct divecomputer fakedc;
struct sample *fake = fake_samples;
alloc_samples(dc, 6);
struct sample *fake = dc->sample;
int i;
fakedc = (*dc);
if (alloc)
fake = malloc(sizeof(fake_samples));
fakedc.sample = fake;
fakedc.samples = 6;
dc->samples = 6;
/* The dive has no samples, so create a few fake ones */
int max_t = dc->duration.seconds;
int max_d = dc->maxdepth.mm;
int avg_d = dc->meandepth.mm;
memset(fake, 0, sizeof(fake_samples));
memset(fake, 0, 6 * sizeof(struct sample));
fake[5].time.seconds = max_t;
for (i = 0; i < 6; i++) {
fake_samples[i].bearing.degrees = -1;
fake_samples[i].ndl.seconds = -1;
fake[i].bearing.degrees = -1;
fake[i].ndl.seconds = -1;
}
if (!max_t || !max_d) {
dc->samples = 0;
return;
}
if (!max_t || !max_d)
return &fakedc;
/*
* We want to fake the profile so that the average
@ -149,10 +145,10 @@ struct divecomputer *fake_dc(struct divecomputer *dc, bool alloc)
* the user supplied data */
fill_samples_no_avg(fake, max_d, max_t, MAX(2.0 * max_d / max_t, 5000.0 / 60));
if (fake[3].time.seconds == 0) { // just a 4 point profile
fakedc.samples = 4;
dc->samples = 4;
fake[3].time.seconds = max_t;
}
return &fakedc;
return;
}
if (avg_d < max_d / 10 || avg_d >= max_d) {
avg_d = (max_d + 10000) / 3;
@ -167,7 +163,7 @@ struct divecomputer *fake_dc(struct divecomputer *dc, bool alloc)
* rate (5 meters per minute) and d_frac (1/3).
*/
if (fill_samples(fake, max_d, avg_d, max_t, 5000.0 / 60, 0.33))
return &fakedc;
return;
/*
* Ok, assume that didn't work because we cannot make the
@ -175,7 +171,7 @@ struct divecomputer *fake_dc(struct divecomputer *dc, bool alloc)
* followed by a much shallower region
*/
if (fill_samples(fake, max_d, avg_d, max_t, 10000.0 / 60, 0.10))
return &fakedc;
return;
/*
* Uhhuh. That didn't work. We'd need to find a good combination that
@ -183,10 +179,9 @@ struct divecomputer *fake_dc(struct divecomputer *dc, bool alloc)
* slopes.
*/
if (fill_samples(fake, max_d, avg_d, max_t, 10000.0, 0.01))
return &fakedc;
return;
/* Even that didn't work? Give up, there's something wrong */
return &fakedc;
}
static void match_id(void *_dc, const char *model, uint32_t deviceid,

View file

@ -7,7 +7,7 @@
extern "C" {
#endif
extern struct divecomputer *fake_dc(struct divecomputer *dc, bool alloc);
extern void fake_dc(struct divecomputer *dc);
extern void set_dc_deviceid(struct divecomputer *dc, unsigned int deviceid);
extern void create_device_node(const char *model, uint32_t deviceid, const char *serial, const char *firmware, const char *nickname);
extern void call_for_each_dc(void *f, void (*callback)(void *, const char *, uint32_t,

View file

@ -714,22 +714,26 @@ void copy_samples(struct divecomputer *s, struct divecomputer *d)
memcpy(d->sample, s->sample, nr * sizeof(struct sample));
}
/* make room for num samples; if not enough space is available, the sample
* array is reallocated and the existing samples are copied. */
void alloc_samples(struct divecomputer *dc, int num)
{
if (num > dc->alloc_samples) {
dc->alloc_samples = (dc->alloc_samples * 3) / 2 + 10;
dc->sample = realloc(dc->sample, dc->alloc_samples * sizeof(struct sample));
if (!dc->sample)
dc->samples = dc->alloc_samples = 0;
}
}
struct sample *prepare_sample(struct divecomputer *dc)
{
if (dc) {
int nr = dc->samples;
int alloc_samples = dc->alloc_samples;
struct sample *sample;
if (nr >= alloc_samples) {
struct sample *newsamples;
alloc_samples = (alloc_samples * 3) / 2 + 10;
newsamples = realloc(dc->sample, alloc_samples * sizeof(struct sample));
if (!newsamples)
return NULL;
dc->alloc_samples = alloc_samples;
dc->sample = newsamples;
}
alloc_samples(dc, nr + 1);
if (!dc->sample)
return NULL;
sample = dc->sample + nr;
memset(sample, 0, sizeof(*sample));
@ -922,7 +926,7 @@ void per_cylinder_mean_depth(struct dive *dive, struct divecomputer *dc, int *me
return;
}
if (!dc->samples)
dc = fake_dc(dc, false);
fake_dc(dc);
struct event *ev = get_next_event(dc->events, "gaschange");
for (i = 0; i < dc->samples; i++) {
struct sample *sample = dc->sample + i;

View file

@ -792,6 +792,7 @@ extern struct dive *clone_dive(struct dive *s);
extern void clear_table(struct dive_table *table);
extern void alloc_samples(struct divecomputer *dc, int num);
extern struct sample *prepare_sample(struct divecomputer *dc);
extern void finish_sample(struct divecomputer *dc);
extern void add_sample_pressure(struct sample *sample, int sensor, int mbar);

View file

@ -1089,9 +1089,9 @@ void QMLManager::commitChanges(QString diveId, QString date, QString location, Q
// so we have depth > 0, a manually added dive and no samples
// let's create an actual profile so the desktop version can work it
// first clear out the mean depth (or the fake_dc() function tries
// to be too clever
// to be too clever)
d->meandepth.mm = d->dc.meandepth.mm = 0;
d->dc = *fake_dc(&d->dc, true);
fake_dc(&d->dc);
}
fixup_dive(d);
DiveListModel::instance()->updateDive(modelIdx, d);

View file

@ -592,9 +592,8 @@ void ProfileWidget2::plotDive(struct dive *d, bool force)
// data that we have
struct divecomputer *currentdc = select_dc(&displayed_dive);
Q_ASSERT(currentdc);
if (!currentdc || !currentdc->samples) {
currentdc = fake_dc(currentdc, false);
}
if (!currentdc || !currentdc->samples)
fake_dc(currentdc);
bool setpointflag = (currentdc->divemode == CCR) && prefs.pp_graphs.po2 && current_dive;
bool sensorflag = setpointflag && prefs.show_ccr_sensors;

View file

@ -99,7 +99,7 @@ void DivePlannerPointsModel::loadFromDive(dive *d)
if (dc->samples)
hasMarkedSamples = dc->sample[0].manually_entered;
else
dc = fake_dc(dc, true);
fake_dc(dc);
// if this dive has more than 100 samples (so it is probably a logged dive),
// average samples so we end up with a total of 100 samples.