[clang-tools-extra] r341544 - [clangd] NFC: Use TopN instead of std::priority_queue

[Kirill Bobyrev via cfe-commits]

Author: omtcyfz
Date: Thu Sep  6 06:15:03 2018
New Revision: 341544

URL: http://llvm.org/viewvc/llvm-project?rev=341544&view=rev
Log:
[clangd] NFC: Use TopN instead of std::priority_queue

Quality.cpp defines a structure for convenient storage of Top N items,
it should be used instead of the `std::priority_queue` with slightly
obscure semantics.

This patch does not affect functionality.

Reviewed By: sammccall

Differential Revision: https://reviews.llvm.org/D51676

Modified:
    clang-tools-extra/trunk/clangd/index/MemIndex.cpp

Modified: clang-tools-extra/trunk/clangd/index/MemIndex.cpp
URL: http://llvm.org/viewvc/llvm-project/clang-tools-extra/trunk/clangd/index/MemIndex.cpp?rev=341544&r1=341543&r2=341544&view=diff
==============================================================================
--- clang-tools-extra/trunk/clangd/index/MemIndex.cpp (original)
+++ clang-tools-extra/trunk/clangd/index/MemIndex.cpp Thu Sep  6 06:15:03 2018
@@ -10,7 +10,7 @@
 #include "MemIndex.h"
 #include "../FuzzyMatch.h"
 #include "../Logger.h"
-#include <queue>
+#include "../Quality.h"
 
 namespace clang {
 namespace clangd {
@@ -26,7 +26,7 @@ bool MemIndex::fuzzyFind(
   assert(!StringRef(Req.Query).contains("::") &&
          "There must be no :: in query.");
 
-  std::priority_queue<std::pair<float, const Symbol *>> Top;
+  TopN<std::pair<float, const Symbol *>> Top(Req.MaxCandidateCount);
   FuzzyMatcher Filter(Req.Query);
   bool More = false;
   for (const auto Pair : Index) {
@@ -38,16 +38,12 @@ bool MemIndex::fuzzyFind(
     if (Req.RestrictForCodeCompletion && !Sym->IsIndexedForCodeCompletion)
       continue;
 
-    if (auto Score = Filter.match(Sym->Name)) {
-      Top.emplace(-*Score * quality(*Sym), Sym);
-      if (Top.size() > Req.MaxCandidateCount) {
-        More = true;
-        Top.pop();
-      }
-    }
+    if (auto Score = Filter.match(Sym->Name))
+      if (Top.push({*Score * quality(*Sym), Sym}))
+        More = true; // An element with smallest score was discarded.
   }
-  for (; !Top.empty(); Top.pop())
-    Callback(*Top.top().second);
+  for (const auto &Item : std::move(Top).items())
+    Callback(*Item.second);
   return More;
 }