From 3c1e7872154e296ac95c8b4212ed13b73145d991 Mon Sep 17 00:00:00 2001
From: Christian Kandeler <christian.kandeler@qt.io>
Date: Mon, 12 Jul 2021 16:52:56 +0200
Subject: [PATCH] ClangCodeModel: Limit result count in clangd-based locator
 searches

clangd memory usage explodes when the workspace/symbol result count hits
the six-digit mark, so prevent that.

Change-Id: Iefc2eeb3da7fe541e2b1d3105818126980fc3323
Reviewed-by: David Schulz <david.schulz@qt.io>
---
 src/libs/languageserverprotocol/workspace.h              | 2 ++
 src/plugins/clangcodemodel/clanggloballocatorfilters.cpp | 5 +++++
 src/plugins/languageclient/locatorfilter.cpp             | 2 ++
 src/plugins/languageclient/locatorfilter.h               | 3 +++
 4 files changed, 12 insertions(+)

diff --git a/src/libs/languageserverprotocol/workspace.h b/src/libs/languageserverprotocol/workspace.h
index 3b0b247b88b..0a745a984fd 100644
--- a/src/libs/languageserverprotocol/workspace.h
+++ b/src/libs/languageserverprotocol/workspace.h
@@ -188,6 +188,8 @@ public:
     QString query() const { return typedValue<QString>(queryKey); }
     void setQuery(const QString &query) { insert(queryKey, query); }
 
+    void setLimit(int limit) { insert("limit", limit); } // clangd extension
+
     bool isValid() const override { return contains(queryKey); }
 };
 
diff --git a/src/plugins/clangcodemodel/clanggloballocatorfilters.cpp b/src/plugins/clangcodemodel/clanggloballocatorfilters.cpp
index 004b10a087d..e979c8928c2 100644
--- a/src/plugins/clangcodemodel/clanggloballocatorfilters.cpp
+++ b/src/plugins/clangcodemodel/clanggloballocatorfilters.cpp
@@ -43,6 +43,8 @@
 namespace ClangCodeModel {
 namespace Internal {
 
+const int MaxResultCount = 10000;
+
 class CppLocatorFilter : public CppTools::CppLocatorFilter
 {
 public:
@@ -67,6 +69,7 @@ public:
         setDefaultShortcutString({});
         setEnabled(false);
         setHidden(true);
+        setMaxResultCount(MaxResultCount);
     }
 };
 
@@ -94,6 +97,7 @@ public:
         setDefaultShortcutString({});
         setEnabled(false);
         setHidden(true);
+        setMaxResultCount(MaxResultCount);
     }
 };
 
@@ -121,6 +125,7 @@ public:
         setDefaultShortcutString({});
         setEnabled(false);
         setHidden(true);
+        setMaxResultCount(MaxResultCount);
     }
 };
 
diff --git a/src/plugins/languageclient/locatorfilter.cpp b/src/plugins/languageclient/locatorfilter.cpp
index b3abe0fc798..ce4fd5c9b5d 100644
--- a/src/plugins/languageclient/locatorfilter.cpp
+++ b/src/plugins/languageclient/locatorfilter.cpp
@@ -230,6 +230,8 @@ void WorkspaceLocatorFilter::prepareSearch(const QString &entry,
 
     WorkspaceSymbolParams params;
     params.setQuery(entry);
+    if (m_maxResultCount > 0)
+        params.setLimit(m_maxResultCount);
 
     QMutexLocker locker(&m_mutex);
     for (auto client : qAsConst(clients)) {
diff --git a/src/plugins/languageclient/locatorfilter.h b/src/plugins/languageclient/locatorfilter.h
index 58da2ddf9c2..6ef079ec45f 100644
--- a/src/plugins/languageclient/locatorfilter.h
+++ b/src/plugins/languageclient/locatorfilter.h
@@ -97,6 +97,8 @@ signals:
 protected:
     explicit WorkspaceLocatorFilter(const QVector<LanguageServerProtocol::SymbolKind> &filter);
 
+    void setMaxResultCount(qint64 limit) { m_maxResultCount = limit; }
+
 private:
     void prepareSearch(const QString &entry, const QVector<Client *> &clients, bool force);
     void handleResponse(Client *client,
@@ -106,6 +108,7 @@ private:
     QMap<Client *, LanguageServerProtocol::MessageId> m_pendingRequests;
     QVector<LanguageServerProtocol::SymbolInformation> m_results;
     QVector<LanguageServerProtocol::SymbolKind> m_filterKinds;
+    qint64 m_maxResultCount = 0;
 };
 
 class LANGUAGECLIENT_EXPORT WorkspaceClassLocatorFilter : public WorkspaceLocatorFilter