further clean, simplify and fix intersection computation

Author: wolfv

src/policy.c

@@ -941,38 +941,31 @@ pool_buildflavorcmp(Pool *pool, Solvable *s1, Solvable *s2)
 
 void intersect_selection(Pool* pool, Id dep, Queue* prev)
 {
-  Queue tmp, res;
+  Queue tmp;
+  int i = 0, j = 0, isectidx = 0;
+
   queue_init(&tmp);
-  // could use queue init buffer as optimization
-  queue_init(&res);
 
   Id* pp, p;
   pp = pool_whatprovides_ptr(pool, dep);
   while ((p = *pp++) != 0)
-  {
     queue_push(&tmp, p);
-  }
 
-  int i = 0, j = 0;
   // set intersection, assuming sorted arrays
-  if (prev)
-  {
-    while (i < prev->count && j < tmp.count) {
-        if (prev->elements[i] < tmp.elements[j])
-            i++;
-        else if (tmp.elements[j] < prev->elements[i])
-            j++;
-        else /* if arr1[i] == arr2[j] */
-        {
-          queue_push(&res, tmp.elements[j]);
-          i++;
-          j++;
-        }
-    }
-  }
+  while (i < prev->count && j < tmp.count) 
+    if (prev->elements[i] < tmp.elements[j])
+      i++;
+    else if (tmp.elements[j] < prev->elements[i])
+      j++;
+    else
+      {
+        if (isectidx != i)
+          prev->elements[isectidx] = prev->elements[i];
+        i++, j++, isectidx++;
+      }
+
+  prev->count = isectidx;
   queue_free(&tmp);
-  queue_free(prev);
-  prev = &res;
 }
 
 int check_deps_unequal(Pool* pool, Queue* q1, Queue* q2, Id name)
@@ -992,37 +985,31 @@ int check_deps_unequal(Pool* pool, Queue* q1, Queue* q2, Id name)
 Id best_matching(Pool* pool, Queue* q, Id name, int* all_have_trackfeatures)
 {
   int first = 1;
-  Id p, *pp;
+  Id dep, p, *pp;
 
   Queue selection;
   queue_init(&selection);
 
-  Id elem;
-
   for (int i = 0; i < q->count; ++i)
   {
-    elem = q->elements[i];
-    if (!ISRELDEP(elem) || GETRELDEP(pool, elem)->name != name) continue;
+    dep = q->elements[i];
+    if (!ISRELDEP(dep) || GETRELDEP(pool, dep)->name != name) continue;
 
     if (first)
     {
-      pp = pool_whatprovides_ptr(pool, elem);
+      pp = pool_whatprovides_ptr(pool, dep);
       while ((p = *pp++) != 0)
-      {
         queue_push(&selection, p);
-      }
       first = 0;
     }
     else
-    {
-      intersect_selection(pool, elem, &selection);
-    }
+      intersect_selection(pool, dep, &selection);
   }
 
   if (selection.count == 0)
     return 0;
 
-  Solvable* best = pool_id2solvable(pool, selection.elements[0]), *stmp;
+  Solvable *stmp, *best = pool_id2solvable(pool, selection.elements[0]);
   int cmp;
 
   *all_have_trackfeatures = 1;
@@ -1083,23 +1070,28 @@ int conda_compare_dependencies(Pool *pool, Solvable *s1, Solvable *s2)
         continue;
       }
 
-    int aht_1, aht_2;
+    int aht_1, aht_2; // all have track features check
     Id b1 = best_matching(pool, &q1, rd1->name, &aht_1);
     Id b2 = best_matching(pool, &q2, rd1->name, &aht_2);
 
-    // one of both is not solvable
-    // add random (high) id here
+    // one of both or both is not solvable...
+    // ignoring this case for now
     if (b1 == 0 || b2 == 0)
       continue;
       // comparison_result += (b1 - b2);
 
-    // if one has deps with track features, and the other does not, downweight
-    // the one with track features
+    // if one has deps with track features, and the other does not, 
+    // downweight the one with track features
     if (aht_1 != aht_2)
       comparison_result += (aht_1 - aht_2) * 100;
 
     comparison_result += pool_evrcmp(pool, b2, b1, 0);
   }
+
+  queue_free(&q1);
+  queue_free(&q2);
+  queue_free(&seen);
+
   return comparison_result;
 }