From 8f79503ed21bfab3bc54a0891008628398c6ca6e Mon Sep 17 00:00:00 2001
From: Tim Jenssen <tim.jenssen@qt.io>
Date: Tue, 5 Jan 2021 19:16:54 +0100
Subject: [PATCH] qmljs: avoid quadratic explosion

Change-Id: Icb184fd5c54a5398ed91b926841f7945dc8a81ec
Reviewed-by: Thomas Hartmann <thomas.hartmann@qt.io>
---
 src/libs/qmljs/qmljsdocument.cpp           | 10 ++++----
 src/libs/qmljs/qmljsimportdependencies.cpp | 17 ++----------
 src/libs/qmljs/qmljsimportdependencies.h   | 30 ++++++++++++++++++++--
 3 files changed, 35 insertions(+), 22 deletions(-)

diff --git a/src/libs/qmljs/qmljsdocument.cpp b/src/libs/qmljs/qmljsdocument.cpp
index ce8b7ba7fe8..df30dcb75ae 100644
--- a/src/libs/qmljs/qmljsdocument.cpp
+++ b/src/libs/qmljs/qmljsdocument.cpp
@@ -479,8 +479,8 @@ void Snapshot::insert(const Document::Ptr &document, bool allowInvalid)
         CoreImport cImport;
         cImport.importId = document->importId();
         cImport.language = document->language();
-        cImport.possibleExports << Export(ImportKey(ImportType::File, fileName),
-                                          QString(), true, QFileInfo(fileName).baseName());
+        cImport.addPossibleExport(Export(ImportKey(ImportType::File, fileName),
+                                          {}, true, QFileInfo(fileName).baseName()));
         cImport.fingerprint = document->fingerprint();
         _dependencies.addCoreImport(cImport);
     }
@@ -526,13 +526,13 @@ void Snapshot::insertLibraryInfo(const QString &path, const LibraryInfo &info)
                     break;
                 ImportKey iKey(ImportType::Library, QStringList(myPath.mid(iPath)).join(QLatin1Char('.')),
                                importKey.majorVersion, importKey.minorVersion);
-                cImport.possibleExports.append(Export(iKey, (iPath == 1) ? QLatin1String("/") :
+                cImport.addPossibleExport(Export(iKey, (iPath == 1) ? QLatin1String("/") :
                      QStringList(myPath.mid(0, iPath)).join(QLatin1Char('/')), true));
             }
         } else {
             QString requiredPath = QStringList(splitPath.mid(0, splitPath.size() - importKey.splitPath.size()))
                     .join(QLatin1String("/"));
-            cImport.possibleExports << Export(importKey, requiredPath, true);
+            cImport.addPossibleExport(Export(importKey, requiredPath, true));
         }
     }
     if (cImport.possibleExports.isEmpty() && splitPath.size() > 0) {
@@ -567,7 +567,7 @@ void Snapshot::insertLibraryInfo(const QString &path, const LibraryInfo &info)
                 break;
             ImportKey iKey(ImportType::Library, QStringList(splitPath.mid(iPath)).join(QLatin1Char('.')),
                            majorVersion, minorVersion);
-            cImport.possibleExports.append(Export(iKey, (iPath == 1) ? QLatin1String("/") :
+            cImport.addPossibleExport(Export(iKey, (iPath == 1) ? QLatin1String("/") :
                 QStringList(splitPath.mid(0, iPath)).join(QLatin1Char('/')), true));
         }
     }
diff --git a/src/libs/qmljs/qmljsimportdependencies.cpp b/src/libs/qmljs/qmljsimportdependencies.cpp
index 26b1e82526c..e6b919eaec3 100644
--- a/src/libs/qmljs/qmljsimportdependencies.cpp
+++ b/src/libs/qmljs/qmljsimportdependencies.cpp
@@ -520,19 +520,6 @@ bool Export::visibleInVContext(const ViewerContext &vContext) const
     return pathRequired.isEmpty() || vContext.paths.contains(pathRequired);
 }
 
-bool operator ==(const Export &i1, const Export &i2)
-{
-    return i1.exportName == i2.exportName
-            && i1.pathRequired == i2.pathRequired
-            && i1.intrinsic == i2.intrinsic
-            && i1.typeName == i2.typeName;
-}
-
-bool operator !=(const Export &i1, const Export &i2)
-{
-    return !(i1 == i2);
-}
-
 CoreImport::CoreImport() : language(Dialect::Qml) { }
 
 CoreImport::CoreImport(const QString &importId, const QList<Export> &possibleExports,
@@ -810,13 +797,13 @@ void ImportDependencies::addExport(const QString &importId, const ImportKey &imp
     if (!m_coreImports.contains(importId)) {
         CoreImport newImport(importId);
         newImport.language = Dialect::AnyLanguage;
-        newImport.possibleExports.append(Export(importKey, requiredPath, false, typeName));
+        newImport.addPossibleExport(Export(importKey, requiredPath, false, typeName));
         m_coreImports.insert(newImport.importId, newImport);
         m_importCache[importKey].append(importId);
         return;
     }
     CoreImport &importValue = m_coreImports[importId];
-    importValue.possibleExports.append(Export(importKey, requiredPath, false, typeName));
+    importValue.addPossibleExport(Export(importKey, requiredPath, false, typeName));
     m_importCache[importKey].append(importId);
     qCDebug(importsLog) << "added export "<< importKey.toString() << " for id " <<importId
                         << " (" << requiredPath << ")";
diff --git a/src/libs/qmljs/qmljsimportdependencies.h b/src/libs/qmljs/qmljsimportdependencies.h
index 903246c034d..41f84915516 100644
--- a/src/libs/qmljs/qmljsimportdependencies.h
+++ b/src/libs/qmljs/qmljsimportdependencies.h
@@ -134,9 +134,27 @@ public:
     QString typeName;
     bool intrinsic;
     bool visibleInVContext(const ViewerContext &vContext) const;
+
+
+    friend bool operator==(const Export &i1, const Export &i2)
+    {
+        return i1.exportName == i2.exportName
+                && i1.pathRequired == i2.pathRequired
+                && i1.intrinsic == i2.intrinsic
+                && i1.typeName == i2.typeName;
+    }
+
+    friend bool operator!=(const Export &i1, const Export &i2)
+    {
+        return !(i1 == i2);
+    }
+
+    friend bool operator<(const Export &i1, const Export &i2)
+    {
+        return std::tie(i1.intrinsic, i1.pathRequired, i1.typeName, i1.exportName)
+            < std::tie(i2.intrinsic, i2.pathRequired, i2.typeName, i2.exportName);
+    }
 };
-bool operator ==(const Export &i1, const Export &i2);
-bool operator !=(const Export &i1, const Export &i2);
 
 class QMLJS_EXPORT CoreImport
 {
@@ -144,6 +162,14 @@ public:
     CoreImport();
     CoreImport(const QString &importId, const QList<Export> &possibleExports = QList<Export>(),
                Dialect language = Dialect::Qml, const QByteArray &fingerprint = QByteArray());
+    template<typename E>
+    void addPossibleExport(E &&e)
+    {
+        auto found = std::lower_bound(possibleExports.begin(), possibleExports.end(), e);
+        if (found == possibleExports.end() || e != *found)
+            possibleExports.insert(found, std::forward<E>(e));
+    }
+
     QString importId;
     QList<Export> possibleExports;
     Dialect language;