1 files changed, 150 insertions, 0 deletions
diff --git a/ratatoeskr/sys/models/KVStorage.php b/ratatoeskr/sys/models/KVStorage.php
new file mode 100644
index 0000000..88c00e2
--- /dev/null
+++ b/ratatoeskr/sys/models/KVStorage.php
@@ -0,0 +1,150 @@
+<?php
+
+namespace r7r\cms\sys\models;
+
+use DoesNotExistError;
+use ArrayAccess;
+use Iterator;
+use Countable;
+use r7r\cms\sys\Database;
+
+/**
+ * An abstract class for a KVStorage
+ */
+abstract class KVStorage implements Countable, ArrayAccess, Iterator
+{
+    private $keybuffer;
+    private $counter;
+    private $silent_mode;
+
+    private $common_vals;
+
+    private $stmt_get;
+    private $stmt_unset;
+    private $stmt_update;
+    private $stmt_create;
+
+    final protected function init(string $sqltable, array $common, Database $db)
+    {
+        $this->silent_mode = false;
+        $this->keybuffer = [];
+
+        $selector = "WHERE ";
+        $fields = "";
+        foreach ($common as $field => $val) {
+            $selector .= "`$field` = ? AND ";
+            $fields .= ", `$field`";
+            $this->common_vals[] = $val;
+        }
+
+        $this->stmt_get = $db->prepStmt("SELECT `value` FROM `$sqltable` $selector `key` = ?");
+        $this->stmt_unset = $db->prepStmt("DELETE FROM `$sqltable` $selector `key` = ?");
+        $this->stmt_update = $db->prepStmt("UPDATE `$sqltable` SET `value` = ? $selector `key` = ?");
+        $this->stmt_create = $db->prepStmt("INSERT INTO `$sqltable` (`key`, `value` $fields) VALUES (?,?" . str_repeat(",?", count($common)) . ")");
+
+        $get_keys = $db->prepStmt("SELECT `key` FROM `$sqltable` $selector 1");
+        $get_keys->execute($this->common_vals);
+        while ($sqlrow = $get_keys->fetch()) {
+            $this->keybuffer[] = $sqlrow["key"];
+        }
+
+        $this->counter = 0;
+    }
+
+    /**
+     * Enable silent mode.
+     *
+     * If the silent mode is enabled, the KVStorage behaves even more like a PHP array, i.e. it just returns NULL,
+     * if an unknown key was requested and does not throw an DoesNotExistError Exception.
+     *
+     * See also {@see KVStorage::disable_silent_mode()}
+     */
+    final public function enable_silent_mode()
+    {
+        $this->silent_mode = true;
+    }
+
+    /**
+     * Disable silent mode.
+     *
+     * See also {@see KVStorage::enable_silent_mode()}
+     */
+    final public function disable_silent_mode()
+    {
+        $this->silent_mode = false;
+    }
+
+    /* Countable interface implementation */
+    final public function count()
+    {
+        return count($this->keybuffer);
+    }
+
+    /* ArrayAccess interface implementation */
+    final public function offsetExists($offset)
+    {
+        return in_array($offset, $this->keybuffer);
+    }
+
+    final public function offsetGet($offset)
+    {
+        if ($this->offsetExists($offset)) {
+            $this->stmt_get->execute(array_merge($this->common_vals, [$offset]));
+            $sqlrow = $this->stmt_get->fetch();
+            $this->stmt_get->closeCursor();
+            return unserialize(base64_decode($sqlrow["value"]));
+        } elseif ($this->silent_mode) {
+            return null;
+        } else {
+            throw new DoesNotExistError();
+        }
+    }
+
+    final public function offsetUnset($offset)
+    {
+        if ($this->offsetExists($offset)) {
+            unset($this->keybuffer[array_search($offset, $this->keybuffer)]);
+            $this->keybuffer = array_merge($this->keybuffer);
+            $this->stmt_unset->execute(array_merge($this->common_vals, [$offset]));
+            $this->stmt_unset->closeCursor();
+        }
+    }
+
+    final public function offsetSet($offset, $value)
+    {
+        if ($this->offsetExists($offset)) {
+            $this->stmt_update->execute(array_merge([base64_encode(serialize($value))], $this->common_vals, [$offset]));
+            $this->stmt_update->closeCursor();
+        } else {
+            $this->stmt_create->execute(array_merge([$offset, base64_encode(serialize($value))], $this->common_vals));
+            $this->stmt_create->closeCursor();
+            $this->keybuffer[] = $offset;
+        }
+    }
+
+    /* Iterator interface implementation */
+    final public function rewind()
+    {
+        return $this->counter = 0;
+    }
+
+    final public function current()
+    {
+        return $this->offsetGet($this->keybuffer[$this->counter]);
+    }
+
+    final public function key()
+    {
+        return $this->keybuffer[$this->counter];
+    }
+
+    final public function next()
+    {
+        ++$this->counter;
+    }
+
+    final public function valid()
+    {
+        return isset($this->keybuffer[$this->counter]);
+    }
+}