backport layout save/restore from svalboard

Author: xyzz

src/index.html

@@ -131,11 +131,73 @@
             document.getElementById("startup").style.display = "none";
         } else if (e.data.cmd == "notify_alive") {
             document.getElementById("startup_btn").disabled = false;
+        } else if (e.data.cmd == "load_layout") {
+            loadLayout();
+        } else if (e.data.cmd == "save_layout") {
+            saveLayout(e.data.layout);
         } else if (e.data.cmd == "fatal_error") {
             alert(e.data.msg);
         }
     }
 
+    const FILE_OPTIONS = {
+        types: [
+            {
+                description: "Vial layout",
+                accept: { "application/json": [".vil"] },
+            },
+        ],
+        excludeAcceptAllOption: false,
+        multiple: false,
+    };
+
+    async function loadLayout() {
+        if (!window.showOpenFilePicker) {
+            alert("File loading API unavailable. Please use a newer browser.");
+            return;
+        }
+
+        const [handle] = await window.showOpenFilePicker(FILE_OPTIONS);
+
+        if (!handle) {
+            return;
+        }
+
+        const file = await handle.getFile();
+        const layout = await file.text();
+
+        PThread.runningWorkers[0].postMessage({
+            cmd: "py",
+            payload: `import webmain;webmain.window.on_layout_loaded(b${JSON.stringify(layout)})`,
+        });
+    }
+
+    async function saveLayout(layout) {
+        if (window.showSaveFilePicker) {
+            // This shows a file chooser dialog. It's a nicer experience
+            // if available, allowing the user to select a target
+            // filename and directory.
+            const handle = await window.showSaveFilePicker(FILE_OPTIONS);
+            const stream = await handle.createWritable();
+            await stream.write(layout);
+            await stream.close();
+        } else {
+            // If the File System API isn't available, we can at least
+            // trigger a simple download with a hardcoded filename.
+            const download = document.createElement('a');
+            download.setAttribute('href', 'data:text/plain;charset=utf-8,' + encodeURIComponent(layout));
+            download.setAttribute('download', 'layout.vil');
+
+            if (document.createEvent) {
+                var event = document.createEvent('MouseEvents');
+                event.initEvent('click', true, true);
+                download.dispatchEvent(event);
+            } else {
+                download.click();
+            }
+        }
+    }
+
     async function connect() {
         var btn = document.getElementById("startup_btn");
 

src/main.c

@@ -133,6 +133,27 @@ static PyObject* vialglue_get_device_desc(PyObject *self, PyObject *args) {
     return PyUnicode_FromString(g_device_desc);
 }
 
+static PyObject * vialglue_load_layout(PyObject *self, PyObject *args) {
+    EM_ASM({
+        postMessage({cmd: "load_layout"});
+    });
+
+    return PyLong_FromLong(0);
+}
+
+static PyObject * vialglue_save_layout(PyObject *self, PyObject *args) {
+    const uint8_t *data;
+
+    if (!PyArg_ParseTuple(args, "y", &data))
+        return NULL;
+
+    EM_ASM({
+        postMessage({cmd: "save_layout", layout: UTF8ToString($0)});
+    }, data);
+
+    return PyLong_FromLong(0);
+}
+
 static PyObject* vialglue_fatal_error(PyObject *self, PyObject *args) {
     const char *msg;
 
@@ -154,6 +175,8 @@ static PyMethodDef VialglueMethods[] = {
     {"unlock_done",  vialglue_unlock_done, METH_VARARGS, ""},
     {"notify_ready",  vialglue_notify_ready, METH_VARARGS, ""},
     {"get_device_desc",  vialglue_get_device_desc, METH_VARARGS, ""},
+    {"load_layout",  vialglue_load_layout, METH_VARARGS, ""},
+    {"save_layout",  vialglue_save_layout, METH_VARARGS, ""},
     {"fatal_error",  vialglue_fatal_error, METH_VARARGS, ""},
     {NULL, NULL, 0, NULL}
 };