CppTools: Make FollowSymbol respect projects

Finding the class definition for a forward declaration or finding the
function definition from its declaration is mostly determined by the
file iteration order. Documents with the most common path prefix are
checked first.

This works fine as long as the files of your project have a common
ancestor. If that's not the case, FollowSymbol might take you to the
definition within another project.

Fix that issue by considering the project part id when constructing the
file iteration order. Since the cached file iteration order now depends
on the projects, ensure to clear it if projects are added, changed or
removed.

Task-number: QTCREATORBUG-15116
Change-Id: I529166bac363959c9fee0b946747fd0370a88809
Reviewed-by: Marco Bubke <marco.bubke@theqtcompany.com>

1 files changed, 26 insertions, 17 deletions

diff --git a/src/plugins/cpptools/symbolfinder.cpp b/src/plugins/cpptools/symbolfinder.cpp
index 26df91bc04..3bc72c00b5 100644
--- a/src/plugins/cpptools/symbolfinder.cpp
+++ b/src/plugins/cpptools/symbolfinder.cpp
@@ -34,6 +34,8 @@
 
 #include "symbolfinder.h"
 
+#include "cppmodelmanager.h"
+
 #include <cplusplus/LookupContext.h>
 
 #include <utils/qtcassert.h>
@@ -357,13 +359,20 @@ QStringList SymbolFinder::fileIterationOrder(const QString &referenceFile, const
             insertCache(referenceFile, doc->fileName());
     }
 
-    QStringList files = m_filePriorityCache.value(referenceFile).values();
+    QStringList files = m_filePriorityCache.value(referenceFile).toStringList();
 
     trackCacheUse(referenceFile);
 
     return files;
 }
 
+void SymbolFinder::clearCache()
+{
+    m_filePriorityCache.clear();
+    m_fileMetaCache.clear();
+    m_recent.clear();
+}
+
 void SymbolFinder::checkCacheConsistency(const QString &referenceFile, const Snapshot &snapshot)
 {
     // We only check for "new" files, which which are in the snapshot but not in the cache.
@@ -376,18 +385,29 @@ void SymbolFinder::checkCacheConsistency(const QString &referenceFile, const Sna
     }
 }
 
+const QString projectPartIdForFile(const QString &filePath)
+{
+    const QList<ProjectPart::Ptr> parts = CppModelManager::instance()->projectPart(filePath);
+    if (!parts.isEmpty())
+        return parts.first()->id();
+    return QString();
+}
+
 void SymbolFinder::clearCache(const QString &referenceFile, const QString &comparingFile)
 {
-    m_filePriorityCache[referenceFile].remove(computeKey(referenceFile, comparingFile),
-                                              comparingFile);
+    m_filePriorityCache[referenceFile].remove(comparingFile, projectPartIdForFile(comparingFile));
     m_fileMetaCache[referenceFile].remove(comparingFile);
 }
 
 void SymbolFinder::insertCache(const QString &referenceFile, const QString &comparingFile)
 {
-    // We want an ordering such that the documents with the most common path appear first.
-    m_filePriorityCache[referenceFile].insert(computeKey(referenceFile, comparingFile),
-                                              comparingFile);
+    FileIterationOrder &order = m_filePriorityCache[referenceFile];
+    if (!order.isValid()) {
+        const auto projectPartId = projectPartIdForFile(referenceFile);
+        order.setReference(referenceFile, projectPartId);
+    }
+    order.insert(comparingFile, projectPartIdForFile(comparingFile));
+
     m_fileMetaCache[referenceFile].insert(comparingFile);
 }
 
@@ -408,14 +428,3 @@ void SymbolFinder::trackCacheUse(const QString &referenceFile)
         m_fileMetaCache.remove(oldest);
     }
 }
-
-int SymbolFinder::computeKey(const QString &referenceFile, const QString &comparingFile)
-{
-    // As similar the path from the comparing file is to the path from the reference file,
-    // the smaller the key is, which is then used for sorting the map.
-    std::pair<QString::const_iterator,
-              QString::const_iterator> r = std::mismatch(referenceFile.begin(),
-                                                         referenceFile.end(),
-                                                         comparingFile.begin());
-    return referenceFile.length() - (r.first - referenceFile.begin());
-}