shithub: puzzles

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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.

--- a/emcc.c

+++ b/emcc.c

@@ -766,9 +766,9 @@

     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;

@@ -797,6 +797,40 @@

 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);

+    }

 }

 /* ----------------------------------------------------------------------

--- a/emccpre.js

+++ b/emccpre.js

@@ -299,6 +299,7 @@

     // 'number' is used for C pointers

     get_save_file = Module.cwrap('get_save_file', 'number', []);

     free_save_file = Module.cwrap('free_save_file', 'void', ['number']);

+    load_game = Module.cwrap('load_game', 'void', ['string', 'number']);

     document.getElementById("save").onclick = function(event) {

         if (dlg_dimmer === null) {

@@ -317,6 +318,31 @@

             dlg_form.appendChild(document.createTextNode("."));

             dlg_form.appendChild(document.createElement("br"));

             dialog_launch(function(event) {

+                dialog_cleanup();

+            });

+        }

+    };

+

+    document.getElementById("load").onclick = function(event) {

+        if (dlg_dimmer === null) {

+            dialog_init("Upload saved-game file");

+            var input = document.createElement("input");

+            input.type = "file";

+            input.multiple = false;

+            dlg_form.appendChild(input);

+            dlg_form.appendChild(document.createElement("br"));

+            dialog_launch(function(event) {

+                if (input.files.length == 1) {

+                    var file = input.files.item(0);

+                    var reader = new FileReader();

+                    reader.addEventListener("loadend", function() {

+                        var string = reader.result;

+                        load_game(string, string.length);

+                    });

+                    reader.readAsBinaryString(file);

+                }

+                dialog_cleanup();

+            }, function(event) {

                 dialog_cleanup();

             });

         }

--- a/emccx.json

+++ b/emccx.json

@@ -18,9 +18,10 @@

     '_timer_callback',

     // Callback from button presses in the UI outside the canvas

     '_command',

-    // Game-saving functions

+    // Game-saving and game-loading functions

     '_get_save_file',

     '_free_save_file',

+    '_load_game',

     // Callbacks to return values from dialog boxes

     '_dlg_return_sval',

     '_dlg_return_ival',

--- a/html/jspage.pl

+++ b/html/jspage.pl

@@ -210,6 +210,7 @@

 ><li id="specific">Enter game ID</li

 ><li id="random">Enter random seed</li

 ><li id="save">Download save file</li

+><li id="load">Upload save file</li

 ></ul></li

 ><li>Type...<ul id="gametype"></ul></li

 ><li class="separator"></li