Settings support, part 1

dlanguilib.visualdproj

@@ -341,6 +341,7 @@
      <File path="src\dlangui\core\i18n.d" />
      <File path="src\dlangui\core\linestream.d" />
      <File path="src\dlangui\core\logger.d" />
+     <File path="src\dlangui\core\settings.d" />
      <File path="src\dlangui\core\signals.d" />
      <File path="src\dlangui\core\stdaction.d" />
      <File path="src\dlangui\core\types.d" />

src/dlangui/core/settings.d

@@ -0,0 +1,117 @@
+module dlangui.core.settings;
+
+import std.range;
+
+/// access to settings
+interface Settings {
+    /// returns true if settings object has specified key
+    bool hasKey(string key);
+    /// returns reference to parent settings
+    @property Settings parent();
+    /// get string by key, returns defValue if no such key
+    string getString(string key, string defValue);
+    /// set string for key, returns old value or null if not set
+    string setString(string key, string value);
+    /// remove setting, returns true if removed, false if no such key
+    bool remove(string key);
+}
+
+/// implementation of settings object
+class SettingsImpl : Settings {
+    protected SettingsImpl _parent;
+    protected SettingsImpl[string] _children;
+    protected string[string] _values;
+    
+    this(SettingsImpl parent = null) {
+        _parent = parent;
+    }
+
+    /// returns reference to parent settings
+    override @property Settings parent() {
+        return _parent;
+    }
+
+    private static bool splitKey(string key, ref string part1, ref string part2) {
+        int dashPos = -1;
+        for (int i = 0; i < key.length; i++) {
+            if (key[i] == '/') {
+                dashPos = i;
+                break;
+            }
+        }
+        if (dashPos >= 0) {
+            // path
+            part1 = key[0 .. dashPos];
+            part2 = key[dashPos + 1 .. $];
+            return true;
+        }
+        return false;
+    }
+
+    /// get string by key, returns defValue if no such key
+    override string getString(string key, string defValue) {
+        string part1, part2;
+        if (splitKey(key, part1, part2)) {
+            // path
+            auto p = (part1 in _children);
+            if (!p)
+                return defValue;
+            return p.getString(part2, defValue);
+        } else {
+            auto p = (key in _values);
+            if (p)
+                return *p;
+            return defValue;
+        }
+    }
+    /// set string for key, returns old value or null if not set
+    override string setString(string key, string value) {
+        string part1, part2;
+        if (splitKey(key, part1, part2)) {
+            // path
+            auto p = (part1 in _children);
+            if (!p) {
+                SettingsImpl newItem = new SettingsImpl(this);
+                _children[part1] = newItem;
+                return newItem.setString(part2, value);
+            } else {
+                return (*p).setString(part2, value);
+            }
+        } else {
+            auto p = (key in _values);
+            string res;
+            if (p)
+                res = *p;
+            _values[key] = value;
+            return res;
+        }
+    }
+    /// returns true if settings object has specified key
+    override bool hasKey(string key) {
+        string part1, part2;
+        if (splitKey(key, part1, part2)) {
+            auto p = (part1 in _children);
+            if (!p) {
+                return false;
+            } else {
+                return (*p).hasKey(part2);
+            }
+        } else {
+            return (key in _values) !is null;
+        }
+    }
+    /// remove setting, returns true if removed, false if no such key
+    bool remove(string key) {
+        string part1, part2;
+        if (splitKey(key, part1, part2)) {
+            auto p = (part1 in _children);
+            if (!p) {
+                return false;
+            } else {
+                return (*p).remove(part2);
+            }
+        } else {
+            return _values.remove(key);
+        }
+    }
+}