solver_sjf: init

include/solver_sjf.h

@@ -0,0 +1,3 @@
+#include "jobs.h"
+
+int solver_sjf(struct job **job, struct job_clist *q, int32_t resources);

src/evanix.c

@@ -8,6 +8,7 @@
 #include "queue.h"
 #include "solver_conformity.h"
 #include "solver_highs.h"
+#include "solver_sjf.h"
 #include "util.h"
 
 static const char usage[] =
@@ -24,7 +25,7 @@ static const char usage[] =
 	"  -p, --pipelined            <bool>  Use evanix build pipeline.\n"
 	"  -l, --check_cache-status   <bool>  Perform cache locality check.\n"
 	"  -c, --close-unused-fd      <bool>  Close stderr on exec.\n"
-	"  -k, --solver     conformity|highs  Solver to use.\n"
+	"  -k, --solver sjf|conformity|highs  Solver to use.\n"
 	"\n";
 
 struct evanix_opts_t evanix_opts = {
@@ -174,6 +175,8 @@ int opts_read(struct evanix_opts_t *opts, char **expr, int argc, char *argv[])
 				opts->solver = solver_conformity;
 			} else if (!strcmp(optarg, "highs")) {
 				opts->solver = solver_highs;
+			} else if (!strcmp(optarg, "sjf")) {
+				opts->solver = solver_sjf;
 			} else {
 				fprintf(stderr,
 					"option -%c has an invalid solver "

src/solver_sjf.c

@@ -0,0 +1,37 @@
+#include <queue.h>
+#include <errno.h>
+
+#include "evanix.h"
+#include "jobs.h"
+#include "solver_sjf.h"
+
+int solver_sjf(struct job **job, struct job_clist *q, int32_t resources)
+{
+	struct job *j;
+	int cost_cur;
+
+	struct job *selected = NULL;
+	int cost_min = -1;
+
+	CIRCLEQ_FOREACH (j, q, clist) {
+		if (j->stale)
+			continue;
+
+		cost_cur = job_cost_recursive(j);
+		if (cost_cur > resources) {
+			job_stale_set(j);
+			if (evanix_opts.solver_report) {
+				printf("❌ refusing to build %s, cost: %d\n",
+				       j->drv_path, job_cost_recursive(j));
+			}
+		}
+
+		if (cost_min < 0 || cost_min > cost_cur) {
+			selected = j;
+			cost_min = cost_cur;
+		}
+	}
+
+	*job = selected;
+	return (cost_min < 0) ? -ESRCH : cost_min;
+}