From c2820c452fbb9b2d26594fb504fe0dfc8206c5a2 Mon Sep 17 00:00:00 2001
From: Michael <heluecht@pirati.ca>
Date: Sun, 30 Apr 2017 19:54:41 +0000
Subject: [PATCH] Delete now works

---
 include/dba.php         | 96 +++++++++++++++++++++++++++++++++++++++++
 include/dbstructure.php |  4 +-
 2 files changed, 98 insertions(+), 2 deletions(-)

diff --git a/include/dba.php b/include/dba.php
index f695902afe..b0d05f4458 100644
--- a/include/dba.php
+++ b/include/dba.php
@@ -23,6 +23,7 @@ class dba {
 	public  $error = false;
 	private $_server_info = '';
 	private static $dbo;
+	private static $relation = array();
 
 	function __construct($server, $user, $pass, $db, $install = false) {
 		$a = get_app();
@@ -753,6 +754,101 @@ class dba {
 		return self::e($sql, $param);
 	}
 
+	/**
+	 * @brief Build the array with the table relations
+	 *
+	 * The array is build from the database definitions in dbstructure.php
+	 *
+	 * This process must only be started once, since the value is cached.
+	 */
+	static private function build_relation_data() {
+		$definition = db_definition();
+
+		foreach ($definition AS $table => $structure) {
+		        foreach ($structure['fields'] AS $field => $field_struct) {
+		                if (isset($field_struct['relation'])) {
+		                        foreach ($field_struct['relation'] AS $rel_table => $rel_field) {
+		                                self::$relation[$rel_table][$rel_field][$table] = $field;
+		                        }
+		                }
+		        }
+		}
+	}
+
+	/**
+	 * @brief Insert a row into a table
+	 *
+	 * @param string $table Table name
+	 * @param array $param parameter array
+	 * @param boolean $in_commit Internal use: Only do a commit after the last delete
+	 * @param array $callstack Internal use: prevent endless loops
+	 *
+	 * @return boolean was the delete successfull?
+	 */
+	static public function delete($table, $param, $in_commit = false, $callstack = array()) {
+
+		// Create a key for the loop prevention
+		$key = $table.':'.implode(':', array_keys($param)).':'.implode(':', $param);
+
+		// We quit when this key already exists in the callstack.
+		if (isset($callstack[$key])) {
+			return true;
+		}
+
+		$callstack[$key] = $key;
+
+		$table = self::$dbo->escape($table);
+
+		// To speed up the whole process we cache the table relations
+		if (count(self::$relation) == 0) {
+			self::build_relation_data();
+		}
+
+		if (!$in_commit) {
+			self::p("COMMIT");
+			self::p("START TRANSACTION");
+		}
+
+		// Is there a relation entry for the table?
+		if (isset(self::$relation[$table])) {
+			foreach (self::$relation[$table] AS $field => $rel_def) {
+				// Fetch all rows that are to be deleted
+				$sql = "SELECT ".self::$dbo->escape($field)." FROM `".$table."` WHERE `".
+					implode("` = ? AND `", array_keys($param))."` = ?";
+
+				$retval = false;
+				$data = self::p($sql, $param);
+				while ($row = self::fetch($data)) {
+					foreach ($rel_def AS $rel_table => $rel_field) {
+						// We do a separate delete process per row
+						$retval = self::delete($rel_table, array($rel_field => $row[$field]), true, $callstack);
+						if (!$retval) {
+							return false;
+						}
+					}
+				}
+				if (!$retval) {
+					return true;
+				}
+			}
+		}
+
+		$sql = "DELETE FROM `".$table."` WHERE `".
+			implode("` = ? AND `", array_keys($param))."` = ?";
+
+		$retval = self::e($sql, $param);
+
+		if (!$in_commit) {
+			if ($retval) {
+				self::p("COMMIT");
+			} else {
+				self::p("ROLLBACK");
+			}
+		}
+
+		return $retval;
+	}
+
 	/**
 	 * @brief Updates rows
 	 *
diff --git a/include/dbstructure.php b/include/dbstructure.php
index 744dc22dcc..cedef40d98 100644
--- a/include/dbstructure.php
+++ b/include/dbstructure.php
@@ -1078,7 +1078,7 @@ function db_definition() {
 					"type" => array("type" => "varchar(255)", "not null" => "1", "default" => ""),
 					"wall" => array("type" => "tinyint(1)", "not null" => "1", "default" => "0"),
 					"gravity" => array("type" => "tinyint(1)", "not null" => "1", "default" => "0"),
-					"parent" => array("type" => "int(10) unsigned", "not null" => "1", "default" => "0"),
+					"parent" => array("type" => "int(10) unsigned", "not null" => "1", "default" => "0", "relation" => array("item" => "id")),
 					"parent-uri" => array("type" => "varchar(255)", "not null" => "1", "default" => ""),
 					"extid" => array("type" => "varchar(255)", "not null" => "1", "default" => ""),
 					"thr-parent" => array("type" => "varchar(255)", "not null" => "1", "default" => ""),
@@ -1284,7 +1284,7 @@ function db_definition() {
 					"notify-id" => array("type" => "int(11)", "not null" => "1", "default" => "0", "relation" => array("notify" => "id")),
 					"master-parent-item" => array("type" => "int(10) unsigned", "not null" => "1", "default" => "0", "relation" => array("item" => "id")),
 					"parent-item" => array("type" => "int(10) unsigned", "not null" => "1", "default" => "0"),
-					"receiver-uid" => array("type" => "int(11)", "not null" => "1", "default" => "0", "relation" => array("user" => "id")),
+					"receiver-uid" => array("type" => "int(11)", "not null" => "1", "default" => "0", "relation" => array("user" => "uid")),
 					),
 			"indexes" => array(
 					"PRIMARY" => array("id"),