Setup project skeletonHEADmaster

1 files changed, 183 insertions, 0 deletions

diff --git a/op.c b/op.c
new file mode 100644
index 0000000..ead1ae5
--- /dev/null
+++ b/op.c
@@ -0,0 +1,183 @@
+/*
+ * nanobbs, a tiny forums software.
+ * Copyright (C) 2025-2026  Xavier Del Campo Romero
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include "op.h"
+#include <libweb/http.h>
+#include <errno.h>
+#include <stddef.h>
+#include <stdlib.h>
+#include <string.h>
+
+struct op
+{
+    sqlite3_stmt *stmt;
+    struct op_cfg cfg;
+};
+
+static int teardown(struct op *const op)
+{
+    int ret = 0, error;
+
+    if (!op)
+        return 0;
+    else if ((error = sqlite3_finalize(op->stmt)) != SQLITE_OK)
+    {
+        fprintf(stderr, "%s: sqlite3_finalize: %s\n", __func__,
+            sqlite3_errstr(error));
+        ret = -1;
+    }
+
+    const struct op_cfg *const cfg = &op->cfg;
+
+    if (cfg->error)
+        cfg->error(cfg->args);
+
+    free(op);
+    return ret;
+}
+
+static void run_error(void *const p)
+{
+    teardown(p);
+}
+
+static int run(const struct http_payload *const pl,
+    struct http_response *const r, void *const user, void *const args)
+{
+    struct op *const op = args;
+    sqlite3_stmt *const stmt = op->stmt;
+    const struct op_cfg *const cfg = &op->cfg;
+    int ret = -1, error = sqlite3_step(stmt);
+
+    switch (error)
+    {
+        case SQLITE_BUSY:
+            break;
+
+        case SQLITE_ROW:
+            if (!cfg->row)
+            {
+                fprintf(stderr, "%s: expected row callback\n", __func__);
+                goto failure;
+            }
+            else if ((ret = cfg->row(op->stmt, pl, r, user, cfg->args)))
+                goto failure;
+
+            break;
+
+        case SQLITE_CONSTRAINT:
+            sqlite3_reset(op->stmt);
+
+            if (!cfg->constraint)
+            {
+                fprintf(stderr, "%s: expected constraint callback\n", __func__);
+                goto failure;
+            }
+            else if ((ret = cfg->constraint(cfg->args)))
+                goto failure;
+
+            /* Fall through. */
+        case SQLITE_DONE:
+        {
+            const int error = sqlite3_finalize(op->stmt);
+
+            if (error != SQLITE_OK)
+            {
+                fprintf(stderr, "%s: sqlite3_finalize: %s\n", __func__,
+                    sqlite3_errstr(error));
+                ret = -1;
+                goto failure;
+            }
+            else if (cfg->end && (ret = cfg->end(pl, r, user, cfg->args)))
+                goto failure;
+
+            free(op);
+        }
+            break;
+
+        default:
+            fprintf(stderr, "%s: sqlite3_step: %s\n", __func__,
+                sqlite3_errstr(error));
+            sqlite3_reset(stmt);
+            goto failure;
+    }
+
+    return 0;
+
+failure:
+
+    if (teardown(op))
+    {
+        fprintf(stderr, "%s: teardown failed\n", __func__);
+        ret = -1;
+    }
+
+    return ret;
+}
+
+void op_resume(struct op *const op, struct http_response *const r)
+{
+    *r = (const struct http_response)
+    {
+        .step.payload = run,
+        .free = run_error,
+        .args = op
+    };
+}
+
+struct op *op_run(sqlite3 *const db, const char *const query,
+    const struct op_cfg *const cfg, struct http_response *const r)
+{
+    sqlite3_stmt *stmt = NULL;
+    struct op *const ret = malloc(sizeof *ret);
+
+    if (!ret)
+    {
+        fprintf(stderr, "%s: malloc(3): %s\n", __func__, strerror(errno));
+        goto failure;
+    }
+
+    const int error = sqlite3_prepare_v2(db, query, -1, &stmt, NULL);
+
+    if (error != SQLITE_OK && error != SQLITE_BUSY)
+    {
+        fprintf(stderr, "%s: sqlite3_prepare_v2 \"%s\": %s\n", __func__,
+            query, sqlite3_errstr(error));
+        goto failure;
+    }
+
+    *r = (const struct http_response)
+    {
+        .step.payload = run,
+        .free = run_error,
+        .args = ret
+    };
+
+    *ret = (const struct op)
+    {
+        .stmt = stmt,
+        .cfg = *cfg
+    };
+
+    return ret;
+
+failure:
+    free(ret);
+    sqlite3_finalize(stmt);
+    return NULL;
+}