Re-organize the code that compares expanded items

The previous approach, which was based on comparing the URLs as
strings, was not only very complex, but also could lead to
inconsistencies in the model, namely, that not all children were
removed from the model when the dir lister reported the parent as
deleted. Later on, this could even lead to a crash.

BUG: 311947
FIXED-IN: 4.11
REVIEW: 108766

1 files changed, 29 insertions, 87 deletions

diff --git a/src/kitemviews/kfileitemmodel.cpp b/src/kitemviews/kfileitemmodel.cpp
index d0fd3d77c..60fc27546 100644
--- a/src/kitemviews/kfileitemmodel.cpp
+++ b/src/kitemviews/kfileitemmodel.cpp
@@ -1,5 +1,6 @@
 /***************************************************************************
  *   Copyright (C) 2011 by Peter Penz <[email protected]>             *
+ *   Copyright (C) 2013 by Frank Reininghaus <[email protected]>    *
  *                                                                         *
  *   This program is free software; you can redistribute it and/or modify  *
  *   it under the terms of the GNU General Public License as published by  *
@@ -1338,11 +1339,34 @@ bool KFileItemModel::lessThan(const ItemData* a, const ItemData* b) const
 {
     int result = 0;
 
-    if (m_expandedParentsCountRoot >= 0) {
-        result = expandedParentsCountCompare(a, b);
-        if (result != 0) {
-            // The items have parents with different expansion levels
-            return (sortOrder() == Qt::AscendingOrder) ? result < 0 : result > 0;
+    if (m_expandedParentsCountRoot >= 0 && a->parent != b->parent) {
+        const int expansionLevelA = a->values.value("expandedParentsCount").toInt();
+        const int expansionLevelB = b->values.value("expandedParentsCount").toInt();
+
+        // If b has a higher expansion level than a, check if a is a parent
+        // of b, and make sure that both expansion levels are equal otherwise.
+        for (int i = expansionLevelB; i > expansionLevelA; --i) {
+            if (b->parent == a) {
+                return true;
+            }
+            b = b->parent;
+        }
+
+        // If a has a higher expansion level than a, check if b is a parent
+        // of a, and make sure that both expansion levels are equal otherwise.
+        for (int i = expansionLevelA; i > expansionLevelB; --i) {
+            if (a->parent == b) {
+                return false;
+            }
+            a = a->parent;
+        }
+
+        Q_ASSERT(a->values.value("expandedParentsCount").toInt() == b->values.value("expandedParentsCount").toInt());
+
+        // Compare the last parents of a and b which are different.
+        while (a->parent != b->parent) {
+            a = a->parent;
+            b = b->parent;
         }
     }
 
@@ -1523,88 +1547,6 @@ int KFileItemModel::stringCompare(const QString& a, const QString& b) const
                             : QString::compare(a, b, Qt::CaseSensitive);
 }
 
-int KFileItemModel::expandedParentsCountCompare(const ItemData* a, const ItemData* b) const
-{
-    const KUrl urlA = a->item.url();
-    const KUrl urlB = b->item.url();
-    if (urlA.directory() == urlB.directory()) {
-        // Both items have the same directory as parent
-        return 0;
-    }
-
-    // Check whether one item is the parent of the other item
-    if (urlA.isParentOf(urlB)) {
-        return (sortOrder() == Qt::AscendingOrder) ? -1 : +1;
-    } else if (urlB.isParentOf(urlA)) {
-        return (sortOrder() == Qt::AscendingOrder) ? +1 : -1;
-    }
-
-    // Determine the maximum common path of both items and
-    // remember the index in 'index'
-    const QString pathA = urlA.path();
-    const QString pathB = urlB.path();
-
-    const int maxIndex = qMin(pathA.length(), pathB.length()) - 1;
-    int index = 0;
-    while (index <= maxIndex && pathA.at(index) == pathB.at(index)) {
-        ++index;
-    }
-    if (index > maxIndex) {
-        index = maxIndex;
-    }
-    while (index > 0 && (pathA.at(index) != QLatin1Char('/') || pathB.at(index) != QLatin1Char('/'))) {
-        --index;
-    }
-
-    // Determine the first sub-path after the common path and
-    // check whether it represents a directory or already a file
-    bool isDirA = true;
-    const QString subPathA = subPath(a->item, pathA, index, &isDirA);
-    bool isDirB = true;
-    const QString subPathB = subPath(b->item, pathB, index, &isDirB);
-
-    if (m_sortDirsFirst || m_sortRole == SizeRole) {
-        if (isDirA && !isDirB) {
-            return (sortOrder() == Qt::AscendingOrder) ? -1 : +1;
-        } else if (!isDirA && isDirB) {
-            return (sortOrder() == Qt::AscendingOrder) ? +1 : -1;
-        }
-    }
-
-    // Compare the items of the parents that represent the first
-    // different path after the common path.
-    const QString parentPathA = pathA.left(index) + subPathA;
-    const QString parentPathB = pathB.left(index) + subPathB;
-
-    const ItemData* parentA = a;
-    while (parentA && parentA->item.url().path() != parentPathA) {
-        parentA = parentA->parent;
-    }
-
-    const ItemData* parentB = b;
-    while (parentB && parentB->item.url().path() != parentPathB) {
-        parentB = parentB->parent;
-    }
-
-    if (parentA && parentB) {
-        return sortRoleCompare(parentA, parentB);
-    }
-
-    kWarning() << "Child items without parent detected:" << a->item.url() << b->item.url();
-    return QString::compare(urlA.url(), urlB.url(), Qt::CaseSensitive);
-}
-
-QString KFileItemModel::subPath(const KFileItem& item,
-                                const QString& itemPath,
-                                int start,
-                                bool* isDir) const
-{
-    Q_ASSERT(isDir);
-    const int pathIndex = itemPath.indexOf('/', start + 1);
-    *isDir = (pathIndex > 0) || item.isDir();
-    return itemPath.mid(start, pathIndex - start);
-}
-
 bool KFileItemModel::useMaximumUpdateInterval() const
 {
     return !m_dirLister->url().isLocalFile();