Support for loading games in Javascript puzzles.

This is done by showing a dialog containing an <input type="file">
through which the user can 'upload' a save file - though, of course,
the 'upload' doesn't go to any HTTP server, but only into the mind of
the Javascript running in the same browser.

It would be even nicer to support drag-and-drop as an alternative UI
for getting the save file into the browser, but that isn't critical to
getting the first version of this feature out of the door.

1 files changed, 36 insertions, 2 deletions

diff --git a/emcc.c b/emcc.c
index 26e1ac2..e25fdf8 100644
--- a/emcc.c
+++ b/emcc.c
@@ -766,9 +766,9 @@ struct savefile_write_ctx {
     size_t pos;
 };
 
-static void savefile_write(void *wctx, void *buf, int len)
+static void savefile_write(void *vctx, void *buf, int len)
 {
-    struct savefile_write_ctx *ctx = (struct savefile_write_ctx *)wctx;
+    struct savefile_write_ctx *ctx = (struct savefile_write_ctx *)vctx;
     if (ctx->buffer)
         memcpy(ctx->buffer + ctx->pos, buf, len);
     ctx->pos += len;
@@ -799,6 +799,40 @@ void free_save_file(char *buffer)
     sfree(buffer);
 }
 
+struct savefile_read_ctx {
+    const char *buffer;
+    int len_remaining;
+};
+
+static int savefile_read(void *vctx, void *buf, int len)
+{
+    struct savefile_read_ctx *ctx = (struct savefile_read_ctx *)vctx;
+    if (ctx->len_remaining < len)
+        return FALSE;
+    memcpy(buf, ctx->buffer, len);
+    ctx->len_remaining -= len;
+    ctx->buffer += len;
+    return TRUE;
+}
+
+void load_game(const char *buffer, int len)
+{
+    struct savefile_read_ctx ctx;
+    const char *err;
+
+    ctx.buffer = buffer;
+    ctx.len_remaining = len;
+    err = midend_deserialise(me, savefile_read, &ctx);
+
+    if (err) {
+        js_error_box(err);
+    } else {
+        select_appropriate_preset();
+        resize();
+        midend_redraw(me);
+    }
+}
+
 /* ----------------------------------------------------------------------
  * Setup function called at page load time. It's called main() because
  * that's the most convenient thing in Emscripten, but it's not main()