--- a/db.c	Mon Jun 14 22:08:24 2021 +0200
+++ b/db.c	Tue Jun 15 20:42:55 2021 +0200
@@ -27,11 +27,21 @@
 
 static sqlite3 *db;
 
+typedef void (*unpacker)(sqlite3_stmt *, struct db_ctx *, void *);
+
 struct str {
 	char *str;
 	SLIST_ENTRY(str) link;
 };
 
+struct list {
+	unpacker unpack;
+	void *data;
+	size_t datasz;
+	size_t elemwidth;
+	struct db_ctx *ctx;
+};
+
 SLIST_HEAD(strlist, str);
 
 static struct strlist *
@@ -71,8 +81,8 @@
 	SLIST_INIT(l);
 }
 
-static inline void
-convert_project(struct db_ctx *ctx, struct project *project, sqlite3_stmt *stmt)
+static void
+project_unpacker(sqlite3_stmt *stmt, struct db_ctx *ctx, struct project *project)
 {
 	project->id = sqlite3_column_int(stmt, 0);
 	project->name = strlist_add(ctx->handle, CHAR(sqlite3_column_text(stmt, 1)));
@@ -81,6 +91,42 @@
 	project->script = strlist_add(ctx->handle, CHAR(sqlite3_column_text(stmt, 4)));
 }
 
+static void
+worker_unpacker(sqlite3_stmt *stmt, struct db_ctx *ctx, struct worker *w)
+{
+	w->id = sqlite3_column_int(stmt, 0);
+	w->name = strlist_add(ctx->handle, CHAR(sqlite3_column_text(stmt, 1)));
+	w->desc = strlist_add(ctx->handle, CHAR(sqlite3_column_text(stmt, 2)));
+}
+
+static void
+job_unpacker(sqlite3_stmt *stmt, struct db_ctx *ctx, struct job *job)
+{
+	job->id = sqlite3_column_int(stmt, 0);
+	job->tag = strlist_add(ctx->handle, CHAR(sqlite3_column_text(stmt, 1)));
+	job->project_id = sqlite3_column_int(stmt, 2);
+}
+
+static void
+vbind(sqlite3_stmt *stmt, const char *fmt, va_list ap)
+{
+	for (int index = 1; *fmt; ++fmt) {
+		switch (*fmt) {
+		case 'i':
+			sqlite3_bind_int(stmt, index++, va_arg(ap, int));
+			break;
+		case 's':
+			sqlite3_bind_text(stmt, index++, va_arg(ap, const char *), -1, SQLITE_STATIC);
+			break;
+		case 'z':
+			sqlite3_bind_int64(stmt, index++, va_arg(ap, size_t));
+			break;
+		default:
+			break;
+		}
+	}
+}
+
 static int
 insert(const char *sql, const char *fmt, ...)
 {
@@ -94,20 +140,7 @@
 		return log_warn("db: %s", sqlite3_errmsg(db)), -1;
 
 	va_start(ap, fmt);
-
-	for (int index = 1; *fmt; ++fmt) {
-		switch (*fmt) {
-		case 'i':
-			sqlite3_bind_int(stmt, index++, va_arg(ap, int));
-			break;
-		case 's':
-			sqlite3_bind_text(stmt, index++, va_arg(ap, const char *), -1, SQLITE_STATIC);
-			break;
-		default:
-			break;
-		}
-	}
-
+	vbind(stmt, fmt, ap);
 	va_end(ap);
 
 	if (sqlite3_step(stmt) != SQLITE_DONE) {
@@ -119,6 +152,43 @@
 	return sqlite3_last_insert_rowid(db);
 }
 
+static ssize_t
+list(struct list *sel, const char *sql, const char *args, ...)
+{
+	sqlite3_stmt *stmt = NULL;
+
+	va_list ap;
+	int step;
+	ssize_t ret = -1;
+	size_t tot = 0;
+
+	sel->ctx->handle = NULL;
+
+	if (sqlite3_prepare(db, sql, -1, &stmt, NULL) != SQLITE_OK)
+		return log_warn("db: %s", sqlite3_errmsg(db)), -1;
+
+	va_start(ap, args);
+	vbind(stmt, args, ap);
+	va_end(ap);
+
+	sel->ctx->handle = strlist_new();
+
+	while (tot < sel->datasz && (step = sqlite3_step(stmt)) == SQLITE_ROW)
+		sel->unpack(stmt, sel->ctx, (unsigned char *)sel->data + (tot++ * sel->elemwidth));
+
+	if (step == SQLITE_OK || step == SQLITE_DONE || step == SQLITE_ROW)
+		ret = tot;
+	else {
+		memset(sel->data, 0, sel->datasz * sel->elemwidth);
+		strlist_free(sel->ctx->handle);
+		sel->ctx->handle = NULL;
+	}
+
+	sqlite3_finalize(stmt);
+
+	return ret;
+}
+
 int
 db_open(const char *path)
 {
@@ -141,130 +211,52 @@
 }
 
 int
-db_project_add(struct project *pj)
+db_project_add(struct project *p)
 {
-	assert(pj);
-
-	sqlite3_stmt *stmt = NULL;
-	int ret = -1;
-
-	if (sqlite3_prepare(db, CHAR(sql_project_add), -1, &stmt, NULL) != SQLITE_OK)
-		goto sqlite3_err;
-
-	sqlite3_bind_text(stmt, 1, pj->name, -1, SQLITE_STATIC);
-	sqlite3_bind_text(stmt, 2, pj->desc, -1, SQLITE_STATIC);
-	sqlite3_bind_text(stmt, 3, pj->url, -1, SQLITE_STATIC);
-	sqlite3_bind_text(stmt, 4, pj->script, -1, SQLITE_STATIC);
-
-	if (sqlite3_step(stmt) != SQLITE_DONE)
-		goto sqlite3_err;
-
-	pj->id = sqlite3_last_insert_rowid(db);
-	ret = 0;
-
-sqlite3_err:
-	if (stmt)
-		sqlite3_finalize(stmt);
-
-	return ret;
+	return (p->id = insert(CHAR(sql_project_add), "ssss", p->name, p->desc,
+	    p->url, p->script)) < 0 ? -1 : 0;
 }
 
 ssize_t
 db_project_list(struct db_ctx *ctx, struct project *projects, size_t projectsz)
 {
-	assert(projects);
-
-	sqlite3_stmt *stmt = NULL;
-	struct project *p = projects;
-	ssize_t ret = 0;
-
-	if (sqlite3_prepare(db, CHAR(sql_project_list), -1, &stmt, NULL) != SQLITE_OK) {
-		log_warn("db: %s", sqlite3_errmsg(db));
-		return -1;
-	}
+	struct list sel = {
+		.unpack = (unpacker)project_unpacker,
+		.data = projects,
+		.datasz = projectsz,
+		.elemwidth = sizeof (*projects),
+		.ctx = ctx
+	};
 
-	sqlite3_bind_int(stmt, 1, projectsz);
-	ctx->handle = strlist_new();
-
-	for (; sqlite3_step(stmt) == SQLITE_ROW && (size_t)ret < projectsz; ++ret, ++p)
-		convert_project(ctx, p, stmt);
-
-	if (stmt)
-		sqlite3_finalize(stmt);
-
-	return ret;
+	return list(&sel, CHAR(sql_project_list), "z", projectsz);
 }
 
 int
 db_project_find(struct db_ctx *ctx, struct project *project)
 {
-	assert(ctx);
-	assert(project);
-
-	sqlite3_stmt *stmt = NULL;
-	int ret = -1;
-
-	ctx->handle = NULL;
-
-	if (sqlite3_prepare(db, CHAR(sql_project_find), -1, &stmt, NULL) != SQLITE_OK)
-		goto sqlite3_err;
-
-	sqlite3_bind_text(stmt, 1, project->name, -1, SQLITE_STATIC);
-
-	if (sqlite3_step(stmt) != SQLITE_ROW)
-		goto sqlite3_err;
+	struct list sel = {
+		.unpack = (unpacker)project_unpacker,
+		.data = project,
+		.datasz = 1,
+		.elemwidth = sizeof (*project),
+		.ctx = ctx
+	};
 
-	ret = 0;
-	ctx->handle = strlist_new();
-	convert_project(ctx, project, stmt);
-
-sqlite3_err:
-	if (ret < 0) {
-		if (ctx->handle)
-			db_ctx_finish(ctx);
-
-		log_warn("db: %s", sqlite3_errmsg(db));
-	}
-	if (stmt)
-		sqlite3_finalize(stmt);
-
-	return ret;
+	return list(&sel, CHAR(sql_project_find), "s", project->name) == 1 ? 0 : -1;
 }
 
 int
 db_project_find_id(struct db_ctx *ctx, struct project *project)
 {
-	assert(ctx);
-	assert(project);
-
-	sqlite3_stmt *stmt = NULL;
-	int ret = -1;
-
-	ctx->handle = NULL;
-
-	if (sqlite3_prepare(db, CHAR(sql_project_find_id), -1, &stmt, NULL) != SQLITE_OK)
-		goto sqlite3_err;
-
-	sqlite3_bind_int(stmt, 1, project->id);
-
-	if (sqlite3_step(stmt) != SQLITE_ROW)
-		goto sqlite3_err;
+	struct list sel = {
+		.unpack = (unpacker)project_unpacker,
+		.data = project,
+		.datasz = 1,
+		.elemwidth = sizeof (*project),
+		.ctx = ctx
+	};
 
-	ret = 0;
-	ctx->handle = strlist_new();
-	convert_project(ctx, project, stmt);
-
-sqlite3_err:
-	if (ret < 0) {
-		if (ctx->handle)
-			db_ctx_finish(ctx);
-
-		log_warn("db: %s", sqlite3_errmsg(db));
-	}
-	if (stmt)
-		sqlite3_finalize(stmt);
-
-	return ret;
+	return list(&sel, CHAR(sql_project_find_id), "i", project->id) == 1 ? 0 : -1;
 }
 
 int
@@ -272,26 +264,7 @@
 {
 	assert(wk);
 
-	sqlite3_stmt *stmt = NULL;
-	int ret = -1;
-
-	if (sqlite3_prepare(db, CHAR(sql_worker_add), -1, &stmt, NULL) != SQLITE_OK)
-		goto sqlite3_err;
-
-	sqlite3_bind_text(stmt, 1, wk->name, -1, SQLITE_STATIC);
-	sqlite3_bind_text(stmt, 2, wk->desc, -1, SQLITE_STATIC);
-
-	if (sqlite3_step(stmt) != SQLITE_DONE)
-		goto sqlite3_err;
-
-	wk->id = sqlite3_last_insert_rowid(db);
-	ret = 0;
-
-sqlite3_err:
-	if (stmt)
-		sqlite3_finalize(stmt);
-
-	return ret;
+	return (wk->id = insert(CHAR(sql_worker_add), "ss", wk->name, wk->desc)) < 0 ? -1 : 0;
 }
 
 ssize_t
@@ -300,111 +273,43 @@
 	assert(ctx);
 	assert(wk);
 
-	sqlite3_stmt *stmt = NULL;
-	struct worker *w = wk;
-	ssize_t ret = -1;
-
-	ctx->handle = NULL;
-
-	if (sqlite3_prepare(db, CHAR(sql_worker_list), -1, &stmt, NULL) != SQLITE_OK)
-		goto sqlite3_err;
-
-	sqlite3_bind_int(stmt, 1, wksz);
-	ctx->handle = strlist_new();
+	struct list sel = {
+		.unpack = (unpacker)worker_unpacker,
+		.data = wk,
+		.datasz = wksz,
+		.elemwidth = sizeof (*wk),
+		.ctx = ctx
+	};
 
-	for (ret = 0; sqlite3_step(stmt) == SQLITE_ROW && (size_t)ret < wksz; ++ret, ++w) {
-		w->id = sqlite3_column_int(stmt, 0);
-		w->name = strlist_add(ctx->handle, CHAR(sqlite3_column_text(stmt, 1)));
-		w->desc = strlist_add(ctx->handle, CHAR(sqlite3_column_text(stmt, 2)));
-	}
-
-sqlite3_err:
-	if (ret < 0) {
-		if (ctx->handle)
-			db_ctx_finish(ctx);
-
-		log_warn("db: %s", sqlite3_errmsg(db));
-	}
-	if (stmt)
-		sqlite3_finalize(stmt);
-
-	return ret;
+	return list(&sel, CHAR(sql_worker_list), "z", wksz);
 }
 
 int
-db_worker_find(struct db_ctx *ctx, struct worker *w)
+db_worker_find(struct db_ctx *ctx, struct worker *wk)
 {
-	assert(ctx);
-	assert(w);
-
-	sqlite3_stmt *stmt = NULL;
-	int ret = -1;
-
-	ctx->handle = NULL;
-
-	if (sqlite3_prepare(db, CHAR(sql_worker_find), -1, &stmt, NULL) != SQLITE_OK)
-		goto sqlite3_err;
-
-	sqlite3_bind_text(stmt, 1, w->name, -1, SQLITE_STATIC);
-
-	if (sqlite3_step(stmt) != SQLITE_ROW)
-		goto sqlite3_err;
+	struct list sel = {
+		.unpack = (unpacker)worker_unpacker,
+		.data = wk,
+		.datasz = 1,
+		.elemwidth = sizeof (*wk),
+		.ctx = ctx
+	};
 
-	ret = 0;
-	ctx->handle = strlist_new();
-	w->id = sqlite3_column_int(stmt, 0);
-	w->name = strlist_add(ctx->handle, CHAR(sqlite3_column_text(stmt, 1)));
-	w->desc = strlist_add(ctx->handle, CHAR(sqlite3_column_text(stmt, 2)));
-
-sqlite3_err:
-	if (ret < 0) {
-		if (ctx->handle)
-			db_ctx_finish(ctx);
-
-		log_warn("db: %s", sqlite3_errmsg(db));
-	}
-	if (stmt)
-		sqlite3_finalize(stmt);
-
-	return ret;
+	return list(&sel, CHAR(sql_worker_find), "s", wk->name);
 }
 
 int
-db_worker_find_id(struct db_ctx *ctx, struct worker *w)
+db_worker_find_id(struct db_ctx *ctx, struct worker *wk)
 {
-	assert(ctx);
-	assert(w);
-
-	sqlite3_stmt *stmt = NULL;
-	int ret = -1;
-
-	ctx->handle = NULL;
-
-	if (sqlite3_prepare(db, CHAR(sql_worker_find_id), -1, &stmt, NULL) != SQLITE_OK)
-		goto sqlite3_err;
-
-	sqlite3_bind_int(stmt, 1, w->id);
-
-	if (sqlite3_step(stmt) != SQLITE_ROW)
-		goto sqlite3_err;
+	struct list sel = {
+		.unpack = (unpacker)worker_unpacker,
+		.data = wk,
+		.datasz = 1,
+		.elemwidth = sizeof (*wk),
+		.ctx = ctx
+	};
 
-	ret = 0;
-	ctx->handle = strlist_new();
-	w->id = sqlite3_column_int(stmt, 0);
-	w->name = strlist_add(ctx->handle, CHAR(sqlite3_column_text(stmt, 1)));
-	w->desc = strlist_add(ctx->handle, CHAR(sqlite3_column_text(stmt, 2)));
-
-sqlite3_err:
-	if (ret < 0) {
-		if (ctx->handle)
-			db_ctx_finish(ctx);
-
-		log_warn("db: %s", sqlite3_errmsg(db));
-	}
-	if (stmt)
-		sqlite3_finalize(stmt);
-
-	return ret;
+	return list(&sel, CHAR(sql_worker_find_id), "i", wk->id);
 }
 
 int
@@ -412,9 +317,8 @@
 {
 	assert(job);
 
-	job->id = insert(CHAR(sql_job_add), "si", job->tag, job->project_id);
-
-	return job->id < 0 ? -1 : 0;
+	return (job->id = insert(CHAR(sql_job_add),
+	    "si", job->tag, job->project_id)) < 0 ? -1 : 0;
 }
 
 ssize_t
@@ -423,27 +327,15 @@
 	assert(ctx);
 	assert(jobs);
 
-	sqlite3_stmt *stmt = NULL;
-	ssize_t ret = 0;
-
-	if (sqlite3_prepare(db, CHAR(sql_job_todo), -1, &stmt, NULL) != SQLITE_OK) {
-		log_warn("db: %s", sqlite3_errmsg(db));
-		return -1;
-	}
-
-	sqlite3_bind_int(stmt, 1, worker_id);
-	sqlite3_bind_int(stmt, 2, jobsz);
-	ctx->handle = strlist_new();
-
-	while (sqlite3_step(stmt) == SQLITE_ROW && (size_t)ret++ < jobsz) {
-		jobs->id = sqlite3_column_int(stmt, 0);
-		jobs->tag = strlist_add(ctx->handle, CHAR(sqlite3_column_text(stmt, 1)));
-		jobs++->project_id = sqlite3_column_int(stmt, 2);
+	struct list sel = {
+		.unpack = (unpacker)job_unpacker,
+		.data = jobs,
+		.datasz = jobsz,
+		.elemwidth = sizeof (*jobs),
+		.ctx = ctx
 	};
 
-	sqlite3_finalize(stmt);
-
-	return ret;
+	return list(&sel, CHAR(sql_job_todo), "iz", worker_id, jobsz);
 }
 
 int
@@ -451,10 +343,8 @@
 {
 	assert(r);
 
-	r->id = insert(CHAR(sql_jobresult_add), "iiis", r->job_id,
-	    r->worker_id, r->exitcode, r->log);
-
-	return r->id < 0 ? -1 : 0;
+	return (r->id = insert(CHAR(sql_jobresult_add), "iiis", r->job_id,
+	    r->worker_id, r->exitcode, r->log)) < 0 ? -1 : 0;
 }
 
 void