dagon.core.persistent

Author: gecko0307

CHANGELOG.md

@@ -1,6 +1,7 @@
 Dagon 0.19.0 - TBD
 ------------------
 - **Core**
+  - `dagon.core.persistent` - simple file-based key-value database that can be used to manage application-specific user data, such as preferences and game saves
   - `InputManager` now supports whitespace-separated keycode names in bindings. Instead of the whitespace, `+` sign is used, e.g. `kb_left+ctrl` for `left ctrl`
   - `Application` now sets console encoding to UTF-8 under Windows
 - **Rendering**

src/dagon/core/package.d

@@ -1,5 +1,5 @@
 /*
-Copyright (c) 2019-2022 Timur Gafarov
+Copyright (c) 2019-2025 Timur Gafarov
 
 Boost Software License - Version 1.0 - August 17th, 2003
 Permission is hereby granted, free of charge, to any person or organization
@@ -36,6 +36,7 @@ public
     import dagon.core.input;
     import dagon.core.keycodes;
     import dagon.core.locale;
+    import dagon.core.persistent;
     import dagon.core.props;
     import dagon.core.time;
     import dagon.core.vfs;

src/dagon/core/persistent.d

@@ -0,0 +1,162 @@
+/*
+Copyright (c) 2025 Timur Gafarov
+
+Boost Software License - Version 1.0 - August 17th, 2003
+Permission is hereby granted, free of charge, to any person or organization
+obtaining a copy of the software and accompanying documentation covered by
+this license (the "Software") to use, reproduce, display, distribute,
+execute, and transmit the Software, and to prepare derivative works of the
+Software, and to permit third-parties to whom the Software is furnished to
+do so, all subject to the following:
+
+The copyright notices in the Software and this entire statement, including
+the above license grant, this restriction and the following disclaimer,
+must be included in all copies of the Software, in whole or in part, and
+all derivative works of the Software, unless such copies or derivative
+works are solely in the form of machine-executable object code generated by
+a source language processor.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
+SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
+FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
+ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+DEALINGS IN THE SOFTWARE.
+*/
+
+module dagon.core.persistent;
+
+import std.stdio: writeln;
+import std.traits;
+import std.file;
+import std.process;
+
+import dlib.core.memory;
+import dlib.core.ownership;
+import dlib.core.stream;
+import dlib.math.vector;
+import dlib.image.color;
+import dlib.text.str;
+import dlib.filesystem.filesystem;
+import dlib.filesystem.stdfs;
+
+import dagon.core.props;
+
+/*
+ * Persistent key-value data storage, uses the same format as dagon.core.config.
+ * Files are stored in home directory under Posix and in %APPDATA% directory
+ * under Windows (C:\Users\<user>\AppData\Roaming).
+ * It can be used to manage application-specific user data, such as preferences
+ * and game saves.
+ */
+class PersistentStorage: Owner
+{
+    StdFileSystem fs;
+    String appDataDir;
+    String filename;
+    String localFilename;
+    Properties props;
+    
+    this(string appFolder, string filename, Owner o)
+    {
+        super(o);
+        fs = New!StdFileSystem();
+        
+        string homeDirVar = "";
+        version(Windows) homeDirVar = "APPDATA";
+        version(Posix) homeDirVar = "~";
+        
+        string dirSeparator;
+        version(Windows) dirSeparator = "\\";
+        version(Posix) dirSeparator = "/";
+        
+        appDataDir = String(environment.get(homeDirVar, ""));
+        if (appDataDir.length)
+        {
+            // Use <appDataDir>/<appFolder>/<filename>
+            String output;
+            this.filename = String(appDataDir);
+            this.filename ~= dirSeparator;
+            this.filename ~= appFolder;
+            
+            fs.createDir(this.filename, true);
+            
+            this.filename ~= dirSeparator;
+            this.filename ~= filename;
+        }
+        else
+        {
+            // Use ./<filename>
+            this.filename = String(filename);
+        }
+        
+        this.localFilename = String(filename);
+        
+        writeln("Using persistent storage file: ", this.filename);
+        
+        props = New!Properties(this);
+        load();
+    }
+    
+    ~this()
+    {
+        appDataDir.free();
+        filename.free();
+        localFilename.free();
+        Delete(fs);
+    }
+    
+    void load()
+    {
+        FileStat stat;
+        if (fs.stat(filename, stat))
+        {
+            auto istrm = fs.openForInput(filename);
+            auto input = readText(istrm);
+            Delete(istrm);
+            props.parse(input);
+            Delete(input);
+        }
+    }
+    
+    void save()
+    {
+        String data = props.serialize();
+        
+        OutputStream strm = fs.openForOutput(filename, FileSystem.create | FileSystem.truncate);
+        strm.writeArray(data);
+        strm.close();
+        Delete(strm);
+        
+        data.free();
+    }
+    
+    DProperty opDispatch(string key)()
+    {
+        return props[key];
+    }
+    
+    void opDispatch(string key, T)(T value)
+    {
+        bool changed = false;
+        static if (is(T == string))
+        {
+            props.set(DPropType.Number, key, value);
+            changed = true;
+        }
+        else static if (is(T == Vector3f) || is(T == Vector4f) || is(T == Color4f))
+        {
+            props.set(DPropType.Vector, key, value.toString());
+            changed = true;
+        }
+        else static if (isNumeric!T)
+        {
+            props.set(DPropType.Number, key, value.to!string);
+            changed = true;
+        }
+        
+        if (changed)
+            save();
+    }
+}