WIP: start working on a way to send EXEC_SQL to the DB thread

This has a deadlock bug that needs to be ironed out.

Signed-off-by: Cole Miller <[email protected]>

src/revamp.c

@@ -3,16 +3,47 @@
 int dbContextInit(struct db_context *ctx, struct config *config)
 {
 	int rv;
-	rv = sem_init(&ctx->sem, 0, 0);
-	if (rv != 0) {
-		return DQLITE_ERROR;
-	}
+	rv = pthread_mutex_init(&ctx->mutex, NULL);
+	assert(rv == 0);
+	rv = pthread_cond_init(&ctx->cond, NULL);
+	assert(rv == 0);
 	registry__init(&ctx->registry, config);
+	ctx->shutdown = false;
+	return 0;
+}
+
+int postExecSqlReq(struct db_context *ctx,
+		struct exec_sql_req req,
+		void *data,
+		void (*cb)(struct exec_sql_req, int, void *))
+{
+	(void)ctx;
+	(void)req;
+	(void)data;
+	(void)cb;
 	return 0;
 }
 
 void dbContextClose(struct db_context *ctx)
 {
 	registry__close(&ctx->registry);
-	sem_destroy(&ctx->sem);
+	pthread_cond_destroy(&ctx->cond);
+	pthread_mutex_destroy(&ctx->mutex);
+}
+
+void *dbTask(void *arg)
+{
+	struct db_context *ctx = arg;
+	int rv;
+
+	rv = pthread_mutex_lock(&ctx->mutex);
+	assert(rv == 0);
+	for (;;) {
+		rv = pthread_cond_wait(&ctx->cond, &ctx->mutex);
+		assert(rv == 0);
+		if (ctx->shutdown) {
+			break;
+		}
+	}
+	return NULL;
 }

src/revamp.h

@@ -1,17 +1,39 @@
 #ifndef DQLITE_REVAMP_H_
 #define DQLITE_REVAMP_H_
 
+#include "lib/queue.h"
 #include "registry.h"
+#include "tuple.h"
 
-#include <semaphore.h>
+#include <pthread.h>
+#include <stdbool.h>
 
 struct db_context
 {
-	sem_t sem;
+	pthread_mutex_t mutex;
+	pthread_cond_t cond;
 	struct registry registry;
+	queue exec_sql_reqs;
+	bool shutdown;
+};
+
+struct exec_sql_req
+{
+	char *db_name;
+	char *sql;
+	struct value *params;
+	queue queue;
 };
 
 int dbContextInit(struct db_context *ctx, struct config *config);
+
+int postExecSqlReq(struct db_context *ctx,
+		struct exec_sql_req req,
+		void *data,
+		void (*cb)(struct exec_sql_req, int, void *));
+
 void dbContextClose(struct db_context *ctx);
 
+void *dbTask(void *arg);
+
 #endif

src/server.c

@@ -15,6 +15,7 @@
 #include "lib/fs.h"
 #include "logger.h"
 #include "protocol.h"
+#include "revamp.h"
 #include "roles.h"
 #include "tracing.h"
 #include "translate.h"
@@ -529,7 +530,10 @@ static void stopCb(uv_async_t *stop)
 	}
 	raft_close(&d->raft, raftCloseCb);
 
-	sem_post(&d->db_ctx->sem);
+	pthread_mutex_lock(&d->db_ctx->mutex);
+	d->db_ctx->shutdown = true;
+	pthread_cond_signal(&d->db_ctx->cond);
+	pthread_mutex_unlock(&d->db_ctx->mutex);
 	pthread_join(d->db_thread, NULL);
 }
 
@@ -676,13 +680,6 @@ static void roleManagementTimerCb(uv_timer_t *handle)
 	RolesAdjust(d);
 }
 
-static void *dbTask(void *arg)
-{
-	struct db_context *ctx = arg;
-	sem_wait(&ctx->sem);
-	return NULL;
-}
-
 static int taskRun(struct dqlite_node *d)
 {
 	int rv;
@@ -697,6 +694,8 @@ static int taskRun(struct dqlite_node *d)
 		return rv;
 	}
 
+	rv = pthread_mutex_lock(&d->db_ctx->mutex);
+	assert(rv == 0);
 	rv = pthread_create(&d->db_thread, NULL, dbTask, d->db_ctx);
 	assert(rv == 0);
 
@@ -754,6 +753,9 @@ static int taskRun(struct dqlite_node *d)
 		return rv;
 	}
 
+	rv = pthread_mutex_unlock(&d->db_ctx->mutex);
+	assert(rv == 0);
+
 	rv = uv_run(&d->loop, UV_RUN_DEFAULT);
 	assert(rv == 0);