Add support for setting and exporting parameters.

1 files changed, 246 insertions, 15 deletions

diff --git a/apps/systemlib/param/param.c b/apps/systemlib/param/param.c
index bb82941a0..315ba187b 100644
--- a/apps/systemlib/param/param.c
+++ b/apps/systemlib/param/param.c
@@ -6,10 +6,13 @@
 
 #include <string.h>
 #include <stdbool.h>
-
+#include <fcntl.h>
 #include <unistd.h>
+#include <err.h>
 
-#include "param.h"
+#include "systemlib/param/param.h"
+#include "systemlib/uthash/utarray.h"
+#include "systemlib/bson/bson.h"
 
 /**
  * Array of static parameter info.
@@ -19,12 +22,78 @@ static const struct param_info_s	*param_info_base = (struct param_info_s *)&__pa
 static const struct param_info_s	*param_info_limit = (struct param_info_s *)&__param_end;
 #define	param_info_count		((unsigned)(param_info_limit - param_info_base))
 
+/**
+ * Storage for modified parameters.
+ */
+struct param_wbuf_s
+{
+	param_t			param;
+	union param_value_u	val;
+	bool			unsaved;
+};
+
+UT_icd		param_icd = {sizeof(struct param_wbuf_s), NULL, NULL, NULL};
+UT_array	*param_values;
+
+static void
+param_lock(void)
+{
+	/* XXX */
+}
+
+static void
+param_unlock(void)
+{
+	/* XXX */
+}
+
+static void
+param_assert_locked(void)
+{
+	/* XXX */
+}
+
 static bool
 handle_in_range(param_t handle) 
 {
 	return (handle < param_info_count);
 }
 
+static int
+param_compare_values(const void *a, const void *b)
+{
+	struct param_wbuf_s *pa = (struct param_wbuf_s *)a;
+	struct param_wbuf_s *pb = (struct param_wbuf_s *)b;
+
+	if (pa->param < pb->param)
+		return -1;
+	if (pa->param > pb->param)
+		return 1;
+	return 0;
+}
+
+static struct param_wbuf_s *
+param_find_changed(param_t param)
+{
+	struct param_wbuf_s	*s = NULL;
+
+	param_assert_locked();
+
+	if (param_values != NULL) {
+#if 0	/* utarray_find requires bsearch, not available */
+		struct param_wbuf_s key;
+		key.param = param;
+		s = utarray_find(param_values, &key, param_compare_values);
+#else
+		while ((s = (struct param_wbuf_s *)utarray_next(param_values, s)) != NULL) {
+			if (s->param == param)
+				break;
+		}
+#endif
+	}
+	return s;
+}
+
 param_t
 param_find(const char *name)
 {
@@ -39,8 +108,17 @@ param_find(const char *name)
 	return PARAM_INVALID;
 }
 
-enum
-param_type_e param_type(param_t param)
+const char *
+param_name(param_t param)
+{
+	if (handle_in_range(param))
+		return param_info_base[param].name;
+
+	return NULL;	
+}
+
+enum param_type_e 
+param_type(param_t param)
 {
 	if (handle_in_range(param))
 		return param_info_base[param].type;
@@ -51,7 +129,6 @@ param_type_e param_type(param_t param)
 size_t
 param_size(param_t param)
 {
-
 	if (handle_in_range(param)) {
 		switch (param_info_base[param].type) {
 		case PARAM_TYPE_INT32:
@@ -72,39 +149,193 @@ param_size(param_t param)
 int
 param_get(param_t param, void *val)
 {
+	int result = -1;
+
+	param_lock();
+
 	if (handle_in_range(param)) {
 
+		struct param_wbuf_s *s = param_find_changed(param);
+		const union param_value_u *v;
+
+		/* work out whether we're fetching the default or a written value */
+		if (s != NULL) {
+			v = &s->val;
+		} else {
+			v = &param_info_base[param].val;
+		}
+
 		/* XXX look for updated value stored elsewhere */
 
 		switch (param_info_base[param].type) {
 		case PARAM_TYPE_INT32:
-			*(int32_t *)val = param_info_base[param].i;
-			return 0;
+			*(int32_t *)val = v->i;
+			result = 0;
+			break;
 
 		case PARAM_TYPE_FLOAT:
-			*(float *)val = param_info_base[param].f;
-			return 0;
+			*(float *)val = v->f;
+			result = 0;
+			break;
 
 		case PARAM_TYPE_STRUCT ... PARAM_TYPE_STRUCT_MAX:
-			memcpy(val, param_info_base[param].p, param_size(param));
-			return 0;
+			*(void **)val = v->p;
+			result = 0;
+			break;
 
 		default:
-			return -1;
+			break;
 		}
+
 	}
-	return -1;
+
+	param_unlock();
+
+	return result;
 }
 
 int
 param_set(param_t param, void *val)
 {
+	int result = -1;
+
+	param_lock();
+
+	if (param_values == NULL)
+		utarray_new(param_values, &param_icd);
+	if (param_values == NULL)
+		goto out;
+
 	if (handle_in_range(param)) {
 
-		/* XXX maintain list of changed values */
+		struct param_wbuf_s *s = param_find_changed(param);
+
+		if (s == NULL) {
 
+			/* construct a new parameter */
+			struct param_wbuf_s buf = { .param = param };
+
+			/* add it to the array and sort */
+			utarray_push_back(param_values, &buf);
+			utarray_sort(param_values, param_compare_values);
+
+			/* find it after sorting */
+			s = param_find_changed(param);
+		}
+
+		/* update the changed value */
+		switch (param_info_base[param].type) {
+		case PARAM_TYPE_INT32:
+			s->val.i = *(int32_t *)val;
+			break;
+
+		case PARAM_TYPE_FLOAT:
+			s->val.f = *(float *)val;
+			break;
+
+		case PARAM_TYPE_STRUCT ... PARAM_TYPE_STRUCT_MAX:
+			s->val.p = *(void **)val;
+			break;
+
+		default:
+			goto out;
+		}
+		s->unsaved = true;
+
+		result = 0;
 	}
-	return -1;
+out:
+	param_unlock();
+	return result;
+}
+
+int
+param_export(const char *filename, bool only_unsaved)
+{
+	struct param_wbuf_s *s;
+	bson	b[1];
+	int	result = -1;
+
+	param_lock();
+
+	bson_init(b);
+
+	while ((s = (struct param_wbuf_s *)utarray_next(param_values, s)) != NULL) {
+		const struct param_info_s *is = &param_info_base[s->param];
+
+		/* 
+		 * if we are only saving values changed since last save, and this
+		 * one hasn't, then skip it
+		 */
+		if (only_unsaved & !s->unsaved)
+			continue;
+		s->unsaved = false;
+
+		switch (is->type) {
+		case PARAM_TYPE_INT32:
+			if (bson_append_int(b, is->name, s->val.i) != BSON_OK)
+				goto out;
+			break;
 
+		case PARAM_TYPE_FLOAT:
+			if (bson_append_double(b, is->name, s->val.f) != BSON_OK)
+				goto out;
+			break;
+
+		case PARAM_TYPE_STRUCT ... PARAM_TYPE_STRUCT_MAX:
+			if (bson_append_binary(b, 
+					       is->name,
+					       is->type,
+					       is->val.p,
+					       is->type - PARAM_TYPE_STRUCT) != BSON_OK)
+				goto out;
+			break;
+		default:
+			goto out;
+		}
+	}
+	result = 0;
+
+out:
+	param_unlock();
+
+	if (result == 0) {
+		bson_finish(b);
+		bson_print(b);
+
+		warnx("object is %d bytes", bson_buffer_size(b));
+
+		if (filename != NULL) {
+			int fd = open(filename, O_CREAT | O_WRONLY | O_TRUNC, 0666);
+			int siz = bson_buffer_size(b);
+			int len = write(fd, bson_data(b), siz);
+			close(fd);
+			if (len != siz)
+				result = -1;
+		}
+	}
+	bson_destroy(b);
+
+	return result;
+}
+
+int
+param_import(const char *filename)
+{
+	return -1;
 }
 
+void
+param_foreach(void (*func)(void *arg, param_t param), void *arg, bool only_changed)
+{
+	param_t	param;
+
+	for (param = 0; handle_in_range(param); param++) {
+
+		/* if requested, skip unchanged values */
+		if (only_changed && (param_find_changed(param) == NULL))
+			continue;
+
+		func(arg, param);
+	}
+}
\ No newline at end of file