ProcessList_buildTree: produce sorted tree

ProcessList_buildTree does not need any particular sort order for
children of the same process or roots. Switching these to the sort order
configured by the user produces sorted tree automatically, making repeat
sort unnecessary.

ProcessList.c

@@ -404,7 +404,7 @@ static int ProcessList_treeProcessCompare(const void* v1, const void* v2) {
    return SPACESHIP_NUMBER(p1->tree_left, p2->tree_left);
 }
 
-static int compareProcessByKnownParentThenPID(const void* v1, const void* v2) {
+static int compareProcessByKnownParentThenNatural(const void* v1, const void* v2) {
    const Process* p1 = (const Process*)v1;
    const Process* p2 = (const Process*)v2;
 
@@ -416,7 +416,7 @@ static int compareProcessByKnownParentThenPID(const void* v1, const void* v2) {
    if (result != 0)
       return result;
 
-   return SPACESHIP_NUMBER(p1->pid, p2->pid);
+   return Process_compare(v1, v2);
 }
 
 // Builds a sorted tree from scratch, without relying on previously gathered information
@@ -449,7 +449,7 @@ static void ProcessList_buildTree(ProcessList* this) {
    }
 
    // Sort by known parent PID (roots first), then PID
-   Vector_quickSortCustomCompare(this->processes, compareProcessByKnownParentThenPID);
+   Vector_quickSortCustomCompare(this->processes, compareProcessByKnownParentThenNatural);
 
    // Find all processes whose parent is not visible
    for (int i = 0; i < vsize; i++) {
@@ -470,14 +470,16 @@ static void ProcessList_buildTree(ProcessList* this) {
       }
    }
 
+   this->needsSort = false;
+
    // Check consistency of the built structures
    assert(Vector_size(this->displayList) == vsize); (void)vsize;
 }
 
 void ProcessList_updateDisplayList(ProcessList* this) {
    if (this->settings->ss->treeView) {
-      ProcessList_updateTreeSet(this);
-      Vector_quickSortCustomCompare(this->displayList, ProcessList_treeProcessCompare);
+      if (this->needsSort)
+         ProcessList_buildTree(this);
    } else {
       if (this->needsSort)
          Vector_insertionSort(this->processes);

ScreenManager.c

@@ -121,14 +121,14 @@ static void checkRecalculation(ScreenManager* this, double* oldTime, int* sortTi
    if (*rescan) {
       *oldTime = newTime;
       int oldUidDigits = Process_uidDigits;
-      // scan processes first - some header values are calculated there
-      ProcessList_scan(pl, this->state->pauseProcessUpdate);
-      // always update header, especially to avoid gaps in graph meters
-      Header_updateData(this->header);
       if (!this->state->pauseProcessUpdate && (*sortTimeout == 0 || this->settings->ss->treeView)) {
          pl->needsSort = true;
          *sortTimeout = 1;
       }
+      // scan processes first - some header values are calculated there
+      ProcessList_scan(pl, this->state->pauseProcessUpdate);
+      // always update header, especially to avoid gaps in graph meters
+      Header_updateData(this->header);
       // force redraw if the number of UID digits was changed
       if (Process_uidDigits != oldUidDigits) {
          *force_redraw = true;