init code of share memory

share_memory/file_lock.go

@@ -0,0 +1,52 @@
+package sharememory
+
+import (
+	"fmt"
+	"os"
+
+	"golang.org/x/sys/unix"
+)
+
+func main() {
+	// 打开文件
+	file, err := os.OpenFile("testfile.txt", os.O_RDWR|os.O_CREATE, 0o666)
+	if err != nil {
+		fmt.Println("Error opening file:", err)
+		return
+	}
+	defer file.Close()
+
+	// 加独占锁
+	fmt.Println("Acquiring exclusive lock...")
+	err = unix.Flock(int(file.Fd()), unix.LOCK_EX)
+	if err != nil {
+		fmt.Println("Error acquiring exclusive lock:", err)
+		return
+	}
+	defer unix.Flock(int(file.Fd()), unix.LOCK_UN) // 释放锁
+
+	fmt.Println("Exclusive lock acquired. Writing to file...")
+	// 这里可以添加写文件的逻辑
+	fmt.Println("Writing complete.")
+
+	// 打开文件
+	file, err = os.OpenFile("testfile.txt", os.O_RDONLY, 0o666)
+	if err != nil {
+		fmt.Println("Error opening file:", err)
+		return
+	}
+	defer file.Close()
+
+	// 加共享锁
+	fmt.Println("Acquiring shared lock...")
+	err = unix.Flock(int(file.Fd()), unix.LOCK_SH)
+	if err != nil {
+		fmt.Println("Error acquiring shared lock:", err)
+		return
+	}
+	defer unix.Flock(int(file.Fd()), unix.LOCK_UN) // 释放锁
+
+	fmt.Println("Shared lock acquired. Reading from file...")
+	// 这里可以添加读文件的逻辑
+	fmt.Println("Reading complete.")
+}

share_memory/share_memeory.go

@@ -0,0 +1,98 @@
+package sharememory
+
+import (
+	"fmt"
+	"unsafe"
+
+	"modelRT/orm"
+
+	"golang.org/x/sys/unix"
+)
+
+// CreateShareMemory defines a function to create a shared memory
+func CreateShareMemory(key uintptr, structSize uintptr) (uintptr, error) {
+	// logger := logger.GetLoggerInstance()
+	// create shared memory
+	shmID, _, err := unix.Syscall(unix.SYS_SHMGET, key, structSize, unix.IPC_CREAT|0o666)
+	if err != 0 {
+		// logger.Error(fmt.Sprintf("create shared memory by key %v failed:", key), zap.Error(err))
+		return 0, fmt.Errorf("create shared memory failed:%w", err)
+	}
+
+	// attach shared memory
+	shmAddr, _, err := unix.Syscall(unix.SYS_SHMAT, shmID, 0, 0)
+	if err != 0 {
+		// logger.Error(fmt.Sprintf("attach shared memory by shmID %v failed:", shmID), zap.Error(err))
+		return 0, fmt.Errorf("attach shared memory failed:%w", err)
+	}
+	return shmAddr, nil
+}
+
+// ReadComponentFromShareMemory defines a function to read component value from shared memory
+func ReadComponentFromShareMemory(key uintptr, componentInfo *orm.Component) error {
+	structSize := unsafe.Sizeof(orm.Component{})
+	shmID, _, err := unix.Syscall(unix.SYS_SHMGET, key, uintptr(int(structSize)), 0o666)
+	if err != 0 {
+		return fmt.Errorf("get shared memory failed:%w", err)
+	}
+
+	shmAddr, _, err := unix.Syscall(unix.SYS_SHMAT, shmID, 0, 0)
+	if err != 0 {
+		return fmt.Errorf("attach shared memory failed:%w", err)
+	}
+
+	// 读取共享内存中的数据
+	componentInfo = (*orm.Component)(unsafe.Pointer(shmAddr + structSize))
+
+	// Detach shared memory
+	unix.Syscall(unix.SYS_SHMDT, shmAddr, 0, 0)
+	return nil
+}
+
+func WriteComponentInShareMemory(key uintptr, componentInfo *orm.Component) error {
+	structSize := unsafe.Sizeof(orm.Component{})
+	shmID, _, err := unix.Syscall(unix.SYS_SHMGET, key, uintptr(int(structSize)), 0o666)
+	if err != 0 {
+		return fmt.Errorf("get shared memory failed:%w", err)
+	}
+
+	shmAddr, _, err := unix.Syscall(unix.SYS_SHMAT, shmID, 0, 0)
+	if err != 0 {
+		return fmt.Errorf("attach shared memory failed:%w", err)
+	}
+
+	obj := (*orm.Component)(unsafe.Pointer(shmAddr + unsafe.Sizeof(structSize)))
+	fmt.Println(obj)
+	obj.ComponentType = componentInfo.ComponentType
+
+	// id integer NOT NULL DEFAULT nextval('component_id_seq'::regclass),
+	// global_uuid uuid NOT NULL DEFAULT gen_random_uuid(),
+	// nspath character varying(32) COLLATE pg_catalog."default",
+	// tag character varying(32) COLLATE pg_catalog."default" NOT NULL,
+	// name character varying(64) COLLATE pg_catalog."default" NOT NULL,
+	// description character varying(512) COLLATE pg_catalog."default" NOT NULL DEFAULT ''::character varying,
+	// grid character varying(64) COLLATE pg_catalog."default" NOT NULL,
+	// zone character varying(64) COLLATE pg_catalog."default" NOT NULL,
+	// station character varying(64) COLLATE pg_catalog."default" NOT NULL,
+	// type integer NOT NULL,
+	// in_service boolean DEFAULT false,
+	// state integer NOT NULL DEFAULT 0,
+	// connected_bus jsonb NOT NULL DEFAULT '{}'::jsonb,
+	// label jsonb NOT NULL DEFAULT '{}'::jsonb,
+	// context jsonb NOT NULL DEFAULT '{}'::jsonb,
+	// page_id integer NOT NULL,
+	// op integer NOT NULL DEFAULT '-1'::integer,
+	// ts timestamp with time zone NOT NULL DEFAULT CURRENT_TIMESTAMP,
+
+	unix.Syscall(unix.SYS_SHMDT, shmAddr, 0, 0)
+	return nil
+}
+
+// DeleteShareMemory defines a function to delete shared memory
+func DeleteShareMemory(key uintptr) error {
+	_, _, err := unix.Syscall(unix.SYS_SHM_UNLINK, key, 0, 0o666)
+	if err != 0 {
+		return fmt.Errorf("get shared memory failed:%w", err)
+	}
+	return nil
+}