From ad90350d0ba3971591554f871ec17544be414038 Mon Sep 17 00:00:00 2001
From: Rhys Weatherley <rhys.weatherley@nokia.com>
Date: Fri, 2 Oct 2009 11:38:10 +1000
Subject: Remove QHash overhead from QGLShareRegister

Move the list of shared contexts from QGLShareRegister into
QGLContextGroup.  There is then no need for the QHash.

Reviewed-by: trustme
---
 src/opengl/qgl.cpp | 40 ++++++++++++++++++----------------------
 src/opengl/qgl_p.h |  8 ++------
 2 files changed, 20 insertions(+), 28 deletions(-)

diff --git a/src/opengl/qgl.cpp b/src/opengl/qgl.cpp
index 665290c..0402268 100644
--- a/src/opengl/qgl.cpp
+++ b/src/opengl/qgl.cpp
@@ -4860,44 +4860,40 @@ void QGLShareRegister::addShare(const QGLContext *context, const QGLContext *sha
         return;
 
     // Make sure 'context' is not already shared with another group of contexts.
-    Q_ASSERT(reg.find(context->d_ptr->group) == reg.end());
     Q_ASSERT(context->d_ptr->group->m_refs == 1);
 
     // Free 'context' group resources and make it use the same resources as 'share'.
+    QGLContextGroup *group = share->d_ptr->group;
     delete context->d_ptr->group;
-    context->d_ptr->group = share->d_ptr->group;
-    context->d_ptr->group->m_refs.ref();
+    context->d_ptr->group = group;
+    group->m_refs.ref();
 
     // Maintain a list of all the contexts in each group of sharing contexts.
-    SharingHash::iterator it = reg.find(share->d_ptr->group);
-    if (it == reg.end())
-        it = reg.insert(share->d_ptr->group, ContextList() << share);
-    it.value() << context;
+    // The list is empty if the "share" context wasn't sharing already.
+    if (group->m_shares.isEmpty())
+        group->m_shares.append(share);
+    group->m_shares.append(context);
 }
 
 QList<const QGLContext *> QGLShareRegister::shares(const QGLContext *context) {
-    SharingHash::const_iterator it = reg.find(context->d_ptr->group);
-    if (it == reg.end())
-        return ContextList();
-    return it.value();
+    return context->d_ptr->group->m_shares;
 }
 
 void QGLShareRegister::removeShare(const QGLContext *context) {
-    SharingHash::iterator it = reg.find(context->d_ptr->group);
-    if (it == reg.end())
+    // Remove the context from the group.
+    QGLContextGroup *group = context->d_ptr->group;
+    if (group->m_shares.isEmpty())
         return;
-
-    int count = it.value().removeAll(context);
-    Q_ASSERT(count == 1);
-    Q_UNUSED(count);
+    group->m_shares.removeAll(context);
 
     // Update context group representative.
-    if (context->d_ptr->group->m_context == context)
-        context->d_ptr->group->m_context = it.value().first();
+    Q_ASSERT(group->m_shares.size() != 0);
+    if (group->m_context == context)
+        group->m_context = group->m_shares[0];
 
-    Q_ASSERT(it.value().size() != 0);
-    if (it.value().size() == 1)
-        reg.erase(it);
+    // If there is only one context left, then make the list empty.
+    if (group->m_shares.size() == 1)
+        group->m_shares.clear();
 }
 
 QGLContextResource::QGLContextResource(FreeFunc f, QObject *parent)
diff --git a/src/opengl/qgl_p.h b/src/opengl/qgl_p.h
index 991c948..1957429 100644
--- a/src/opengl/qgl_p.h
+++ b/src/opengl/qgl_p.h
@@ -233,6 +233,7 @@ private:
 
     QGLExtensionFuncs m_extensionFuncs;
     const QGLContext *m_context; // context group's representative
+    QList<const QGLContext *> m_shares;
     QAtomicInt m_refs;
 
     friend class QGLShareRegister;
@@ -401,16 +402,11 @@ class Q_AUTOTEST_EXPORT QGLShareRegister
 {
 public:
     QGLShareRegister() {}
-    ~QGLShareRegister() { reg.clear(); }
+    ~QGLShareRegister() {}
 
     void addShare(const QGLContext *context, const QGLContext *share);
     QList<const QGLContext *> shares(const QGLContext *context);
     void removeShare(const QGLContext *context);
-private:
-    // Use a context's 'group' pointer to uniquely identify a group.
-    typedef QList<const QGLContext *> ContextList;
-    typedef QHash<const QGLContextGroup *, ContextList> SharingHash;
-    SharingHash reg;
 };
 
 extern Q_OPENGL_EXPORT QGLShareRegister* qgl_share_reg();
-- 
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