1 files changed, 277 insertions, 0 deletions
diff --git a/v_windows/v/vlib/pg/pg.v b/v_windows/v/vlib/pg/pg.v
new file mode 100644
index 0000000..9e2d7e7
--- /dev/null
+++ b/v_windows/v/vlib/pg/pg.v
@@ -0,0 +1,277 @@
+module pg
+
+import io
+
+#flag -lpq
+#flag linux -I/usr/include/postgresql
+#flag darwin -I/opt/local/include/postgresql11
+#flag windows -I @VEXEROOT/thirdparty/pg/include
+#flag windows -L @VEXEROOT/thirdparty/pg/win64
+
+// PostgreSQL Source Code
+// https://doxygen.postgresql.org/libpq-fe_8h.html
+#include <libpq-fe.h>
+// for orm
+#include <arpa/inet.h>
+
+pub struct DB {
+mut:
+	conn &C.PGconn
+}
+
+pub struct Row {
+pub mut:
+	vals []string
+}
+
+struct C.PGResult {
+}
+
+pub struct Config {
+pub:
+	host     string
+	port     int = 5432
+	user     string
+	password string
+	dbname   string
+}
+
+fn C.PQconnectdb(a &byte) &C.PGconn
+
+fn C.PQerrorMessage(voidptr) &byte
+
+fn C.PQgetvalue(&C.PGResult, int, int) &byte
+
+fn C.PQstatus(voidptr) int
+
+fn C.PQresultStatus(voidptr) int
+
+fn C.PQntuples(&C.PGResult) int
+
+fn C.PQnfields(&C.PGResult) int
+
+fn C.PQexec(voidptr, &byte) &C.PGResult
+
+// Params:
+// const Oid *paramTypes
+// const char *const *paramValues
+// const int *paramLengths
+// const int *paramFormats
+fn C.PQexecParams(conn voidptr, command &byte, nParams int, paramTypes int, paramValues &byte, paramLengths int, paramFormats int, resultFormat int) &C.PGResult
+
+fn C.PQputCopyData(conn voidptr, buffer &byte, nbytes int) int
+
+fn C.PQputCopyEnd(voidptr, &byte) int
+
+fn C.PQgetCopyData(conn voidptr, buffer &&byte, async int) int
+
+fn C.PQclear(&C.PGResult) voidptr
+
+fn C.PQfreemem(voidptr)
+
+fn C.PQfinish(voidptr)
+
+// connect makes a new connection to the database server using
+// the parameters from the `Config` structure, returning
+// a connection error when something goes wrong
+pub fn connect(config Config) ?DB {
+	conninfo := 'host=$config.host port=$config.port user=$config.user dbname=$config.dbname password=$config.password'
+	conn := C.PQconnectdb(conninfo.str)
+	if conn == 0 {
+		return error('libpq memory allocation error')
+	}
+	status := C.PQstatus(conn)
+	if status != C.CONNECTION_OK {
+		// We force the construction of a new string as the
+		// error message will be freed by the next `PQfinish`
+		// call
+		c_error_msg := unsafe { C.PQerrorMessage(conn).vstring() }
+		error_msg := '$c_error_msg'
+		C.PQfinish(conn)
+		return error('Connection to a PG database failed: $error_msg')
+	}
+	return DB{
+		conn: conn
+	}
+}
+
+fn res_to_rows(res voidptr) []Row {
+	nr_rows := C.PQntuples(res)
+	nr_cols := C.PQnfields(res)
+
+	mut rows := []Row{}
+	for i in 0 .. nr_rows {
+		mut row := Row{}
+		for j in 0 .. nr_cols {
+			val := C.PQgetvalue(res, i, j)
+			sval := unsafe { val.vstring() }
+			row.vals << sval
+		}
+		rows << row
+	}
+
+	C.PQclear(res)
+	return rows
+}
+
+// close frees the underlying resource allocated by the database connection
+pub fn (db DB) close() {
+	C.PQfinish(db.conn)
+}
+
+// q_int submit a command to the database server and
+// returns an the first field in the first tuple
+// converted to an int. If no row is found or on
+// command failure, an error is returned
+pub fn (db DB) q_int(query string) ?int {
+	rows := db.exec(query) ?
+	if rows.len == 0 {
+		return error('q_int "$query" not found')
+	}
+	row := rows[0]
+	if row.vals.len == 0 {
+		return 0
+	}
+	val := row.vals[0]
+	return val.int()
+}
+
+// q_string submit a command to the database server and
+// returns an the first field in the first tuple
+// as a string. If no row is found or on
+// command failure, an error is returned
+pub fn (db DB) q_string(query string) ?string {
+	rows := db.exec(query) ?
+	if rows.len == 0 {
+		return error('q_string "$query" not found')
+	}
+	row := rows[0]
+	if row.vals.len == 0 {
+		return ''
+	}
+	val := row.vals[0]
+	return val
+}
+
+// q_strings submit a command to the database server and
+// returns the resulting row set. Alias of `exec`
+pub fn (db DB) q_strings(query string) ?[]Row {
+	return db.exec(query)
+}
+
+// exec submit a command to the database server and wait
+// for the result, returning an error on failure and a
+// row set on success
+pub fn (db DB) exec(query string) ?[]Row {
+	res := C.PQexec(db.conn, query.str)
+	return db.handle_error_or_result(res, 'exec')
+}
+
+fn rows_first_or_empty(rows []Row) ?Row {
+	if rows.len == 0 {
+		return error('no row')
+	}
+	return rows[0]
+}
+
+pub fn (db DB) exec_one(query string) ?Row {
+	res := C.PQexec(db.conn, query.str)
+	e := unsafe { C.PQerrorMessage(db.conn).vstring() }
+	if e != '' {
+		return error('pg exec error: "$e"')
+	}
+	row := rows_first_or_empty(res_to_rows(res)) ?
+	return row
+}
+
+// exec_param_many executes a query with the provided parameters
+pub fn (db DB) exec_param_many(query string, params []string) ?[]Row {
+	mut param_vals := []&char{len: params.len}
+	for i in 0 .. params.len {
+		param_vals[i] = params[i].str
+	}
+
+	res := C.PQexecParams(db.conn, query.str, params.len, 0, param_vals.data, 0, 0, 0)
+	return db.handle_error_or_result(res, 'exec_param_many')
+}
+
+pub fn (db DB) exec_param2(query string, param string, param2 string) ?[]Row {
+	return db.exec_param_many(query, [param, param2])
+}
+
+pub fn (db DB) exec_param(query string, param string) ?[]Row {
+	return db.exec_param_many(query, [param])
+}
+
+fn (db DB) handle_error_or_result(res voidptr, elabel string) ?[]Row {
+	e := unsafe { C.PQerrorMessage(db.conn).vstring() }
+	if e != '' {
+		C.PQclear(res)
+		return error('pg $elabel error:\n$e')
+	}
+	return res_to_rows(res)
+}
+
+// copy_expert execute COPY commands
+// https://www.postgresql.org/docs/9.5/libpq-copy.html
+pub fn (db DB) copy_expert(query string, file io.ReaderWriter) ?int {
+	res := C.PQexec(db.conn, query.str)
+	status := C.PQresultStatus(res)
+
+	defer {
+		C.PQclear(res)
+	}
+
+	e := unsafe { C.PQerrorMessage(db.conn).vstring() }
+	if e != '' {
+		return error('pg copy error:\n$e')
+	}
+
+	if status == C.PGRES_COPY_IN {
+		mut buf := []byte{len: 4 * 1024}
+		for {
+			n := file.read(mut buf) or {
+				msg := 'pg copy error: Failed to read from input'
+				C.PQputCopyEnd(db.conn, msg.str)
+				return err
+			}
+			if n <= 0 {
+				break
+			}
+
+			code := C.PQputCopyData(db.conn, buf.data, n)
+			if code == -1 {
+				return error('pg copy error: Failed to send data, code=$code')
+			}
+		}
+
+		code := C.PQputCopyEnd(db.conn, 0)
+
+		if code != 1 {
+			return error('pg copy error: Failed to finish copy command, code: $code')
+		}
+	} else if status == C.PGRES_COPY_OUT {
+		for {
+			address := &byte(0)
+			n_bytes := C.PQgetCopyData(db.conn, &address, 0)
+			if n_bytes > 0 {
+				mut local_buf := []byte{len: n_bytes}
+				unsafe { C.memcpy(&byte(local_buf.data), address, n_bytes) }
+				file.write(local_buf) or {
+					C.PQfreemem(address)
+					return err
+				}
+			} else if n_bytes == -1 {
+				break
+			} else if n_bytes == -2 {
+				// consult PQerrorMessage for the reason
+				return error('pg copy error: read error')
+			}
+			if address != 0 {
+				C.PQfreemem(address)
+			}
+		}
+	}
+
+	return 0
+}