parse-events: Add pevent_filter_make_string()

Add the function pevent_filter_make_string() that will return an
allocated string that translates a filter of an event. This can
be used to display the defined filters back to the user.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

2 files changed, 262 insertions, 0 deletions

diff --git a/parse-events.h b/parse-events.h
index 1573869..641aaf2 100644
--- a/parse-events.h
+++ b/parse-events.h
@@ -597,4 +597,6 @@ void pevent_filter_reset(struct event_filter *filter);
 
 void pevent_filter_free(struct event_filter *filter);
 
+char *pevent_filter_make_string(struct event_filter *filter, int event_id);
+
 #endif /* _PARSE_EVENTS_H */
diff --git a/parse-filter.c b/parse-filter.c
index 8944644..c047560 100644
--- a/parse-filter.c
+++ b/parse-filter.c
@@ -1071,3 +1071,263 @@ int pevent_filter_match(struct event_filter *filter,
                 FILTER_MATCH : FILTER_MISS;
 }
 
+static char *arg_to_str(struct event_filter *filter, struct filter_arg *arg);
+
+static char *op_to_str(struct event_filter *filter, struct filter_arg *arg)
+{
+        char *str = NULL;
+        char *left = NULL;
+        char *right = NULL;
+        char *op = NULL;
+        int left_val = -1;
+        int right_val = -1;
+        int val;
+        int len;
+
+        switch (arg->op.type) {
+        case FILTER_OP_AND:
+                op = "&&";
+                /* fall through */
+        case FILTER_OP_OR:
+                if (!op)
+                        op = "||";
+
+                left = arg_to_str(filter, arg->op.left);
+                right = arg_to_str(filter, arg->op.right);
+                if (!left || !right)
+                        break;
+
+                /* Try to consolidate boolean values */
+                if (strcmp(left, "TRUE") == 0)
+                        left_val = 1;
+                else if (strcmp(left, "FALSE") == 0)
+                        left_val = 0;
+
+                if (strcmp(right, "TRUE") == 0)
+                        right_val = 1;
+                else if (strcmp(right, "FALSE") == 0)
+                        right_val = 0;
+
+                if (left_val >= 0) {
+                        if ((arg->op.type == FILTER_OP_AND && !left_val) ||
+                            (arg->op.type == FILTER_OP_OR && left_val)) {
+                                /* Just return left value */
+                                str = left;
+                                left = NULL;
+                                break;
+                        }
+                        if (right_val >= 0) {
+                                /* just evaluate this. */
+                                val = 0;
+                                switch (arg->op.type) {
+                                case FILTER_OP_AND:
+                                        val = left_val && right_val;
+                                        break;
+                                case FILTER_OP_OR:
+                                        val = left_val || right_val;
+                                        break;
+                                default:
+                                        break;
+                                }
+                                str = malloc_or_die(6);
+                                if (val)
+                                        strcpy(str, "TRUE");
+                                else
+                                        strcpy(str, "FALSE");
+                                break;
+                        }
+                }
+                if (right_val >= 0) {
+                        if ((arg->op.type == FILTER_OP_AND && !right_val) ||
+                            (arg->op.type == FILTER_OP_OR && right_val)) {
+                                /* Just return right value */
+                                str = right;
+                                right = NULL;
+                                break;
+                        }
+                        /* The right value is meaningless */
+                        str = left;
+                        left = NULL;
+                        break;
+                }
+
+                len = strlen(left) + strlen(right) + strlen(op) + 10;
+                str = malloc_or_die(len);
+                snprintf(str, len, "(%s) %s (%s)",
+                         left, op, right);
+                break;
+
+        case FILTER_OP_NOT:
+                op = "!";
+                right = arg_to_str(filter, arg->op.right);
+                if (!right)
+                        break;
+
+                /* See if we can consolidate */
+                if (strcmp(right, "TRUE") == 0)
+                        right_val = 1;
+                else if (strcmp(right, "FALSE") == 0)
+                        right_val = 0;
+                if (right_val >= 0) {
+                        /* just return the opposite */
+                        str = malloc_or_die(6);
+                        if (right_val)
+                                strcpy(str, "FALSE");
+                        else
+                                strcpy(str, "TRUE");
+                        break;
+                }
+                len = strlen(right) + strlen(op) + 3;
+                str = malloc_or_die(len);
+                snprintf(str, len, "%s(%s)", op, right);
+                break;
+
+        default:
+                /* ?? */
+                break;
+        }
+        free(left);
+        free(right);
+        return str;
+}
+
+static char *num_to_str(struct event_filter *filter, struct filter_arg *arg)
+{
+        char *str = NULL;
+        char *op = NULL;
+        int len;
+
+        switch (arg->num.type) {
+        case FILTER_CMP_EQ:
+                op = "==";
+                /* fall through */
+        case FILTER_CMP_NE:
+                if (!op)
+                        op = "!=";
+                /* fall through */
+        case FILTER_CMP_GT:
+                if (!op)
+                        op = ">";
+                /* fall through */
+        case FILTER_CMP_LT:
+                if (!op)
+                        op = "<";
+                /* fall through */
+        case FILTER_CMP_GE:
+                if (!op)
+                        op = ">=";
+                /* fall through */
+        case FILTER_CMP_LE:
+                if (!op)
+                        op = "<=";
+
+                len = strlen(arg->num.field->name) + strlen(op) + 30;
+                str = malloc_or_die(len);
+                if (arg->num.field->flags & FIELD_IS_SIGNED)
+                        snprintf(str, len, "%s %s %lld",
+                                 arg->num.field->name,
+                                 op, arg->num.val);
+                else
+                        snprintf(str, len, "%s %s %llu",
+                                 arg->num.field->name,
+                                 op, arg->num.val);
+                break;
+
+        default:
+                /* ?? */
+                break;
+        }
+        return str;
+}
+
+static char *str_to_str(struct event_filter *filter, struct filter_arg *arg)
+{
+        char *str = NULL;
+        char *op = NULL;
+        int len;
+
+        switch (arg->str.type) {
+        case FILTER_CMP_MATCH:
+                op = "==";
+                /* fall through */
+        case FILTER_CMP_NOT_MATCH:
+                if (!op)
+                        op = "!=";
+                /* fall through */
+        case FILTER_CMP_REGEX:
+                if (!op)
+                        op = "=~";
+                /* fall through */
+        case FILTER_CMP_NOT_REGEX:
+                if (!op)
+                        op = "!~";
+
+                len = strlen(arg->str.field->name) + strlen(op) +
+                        strlen(arg->str.val) + 6;
+                str = malloc_or_die(len);
+                snprintf(str, len, "%s %s \"%s\"",
+                         arg->str.field->name,
+                         op, arg->str.val);
+                break;
+
+        default:
+                /* ?? */
+                break;
+        }
+        return str;
+}
+
+static char *arg_to_str(struct event_filter *filter, struct filter_arg *arg)
+{
+        char *str;
+
+        switch (arg->type) {
+        case FILTER_ARG_BOOLEAN:
+                str = malloc_or_die(6);
+                if (arg->bool.value)
+                        strcpy(str, "TRUE");
+                else
+                        strcpy(str, "FALSE");
+                return str;
+
+        case FILTER_ARG_OP:
+                return op_to_str(filter, arg);
+
+        case FILTER_ARG_NUM:
+                return num_to_str(filter, arg);
+
+        case FILTER_ARG_STR:
+                return str_to_str(filter, arg);
+
+        default:
+                /* ?? */
+                return NULL;
+        }
+
+}
+
+/**
+ * pevent_filter_make_string - return a string showing the filter
+ * @filter: filter struct with filter information
+ * @event_id: the event id to return the filter string with
+ *
+ * Returns a string that displays the filter contents.
+ *  This string must be freed with free(str).
+ *  NULL is returned if no filter is found.
+ */
+char *
+pevent_filter_make_string(struct event_filter *filter, int event_id)
+{
+        struct filter_type *filter_type;
+
+        if (!filter->filters)
+                return NULL;
+
+        filter_type = find_filter_type(filter, event_id);
+
+        if (!filter_type)
+                return NULL;
+
+        return arg_to_str(filter, filter_type->filter);
+}
+