Implement new plugin mechanism

moc can now embed meta information about the plugin
inside the plugin itself. This information can
be queried by Qt without having to load the plugin.

Source compatibility with the old plugin loading
mechanism is still there, but will be removed before
Qt 5.0.

Change-Id: I03e4196ddfed07d0fe94acca40d5de8a6ce7f920
Reviewed-by: João Abecasis <joao.abecasis@nokia.com>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

1 files changed, 128 insertions, 31 deletions

diff --git a/src/corelib/plugin/qlibrary.cpp b/src/corelib/plugin/qlibrary.cpp
index dc08b32db1..b171577184 100644
--- a/src/corelib/plugin/qlibrary.cpp
+++ b/src/corelib/plugin/qlibrary.cpp
@@ -60,6 +60,9 @@
 #include <qdebug.h>
 #include <qvector.h>
 #include <qdir.h>
+#include <qendian.h>
+#include <qjsondocument.h>
+#include <qjsonvalue.h>
 #include "qelfparser_p.h"
 
 QT_BEGIN_NAMESPACE
@@ -330,7 +333,7 @@ static long qt_find_pattern(const char *s, ulong s_len,
                 information could not be read.
   Returns  true if version information is present and successfully read.
 */
-static bool qt_unix_query(const QString &library, uint *version, bool *debug, QLibraryPrivate *lib = 0)
+static bool qt_unix_query(const QString &library, QLibraryPrivate *lib)
 {
     QFile file(library);
     if (!file.open(QIODevice::ReadOnly)) {
@@ -357,35 +360,71 @@ static bool qt_unix_query(const QString &library, uint *version, bool *debug, QL
     /*
        ELF binaries on GNU, have .qplugin sections.
     */
+    bool hasMetaData = false;
     long pos = 0;
-    const char pattern[] = "pattern=QT_PLUGIN_VERIFICATION_DATA";
+    const char oldPattern[] = "pattern=QT_PLUGIN_VERIFICATION_DATA";
+    const ulong oldPlen = qstrlen(oldPattern);
+    const char pattern[] = "QTMETADATA  ";
     const ulong plen = qstrlen(pattern);
 #if defined (Q_OF_ELF) && defined(Q_CC_GNU)
     int r = QElfParser().parse(filedata, fdlen, library, lib, &pos, &fdlen);
-    if (r == QElfParser::NoQtSection) {
+    if (r == QElfParser::Corrupt || r == QElfParser::NotElf) {
+            if (lib && qt_debug_component()) {
+                qWarning("QElfParser: %s",qPrintable(lib->errorString));
+            }
+            return false;
+    } else if (r == QElfParser::NoQtSection || r == QElfParser::QtPluginSection) {
         if (pos > 0) {
             // find inside .rodata
-            long rel = qt_find_pattern(filedata + pos, fdlen, pattern, plen);
+            long rel = qt_find_pattern(filedata + pos, fdlen, oldPattern, oldPlen);
             if (rel < 0) {
                 pos = -1;
             } else {
                 pos += rel;
             }
         } else {
-            pos = qt_find_pattern(filedata, fdlen, pattern, plen);
-        }
-    } else if (r != QElfParser::Ok) {
-        if (lib && qt_debug_component()) {
-            qWarning("QElfParser: %s",qPrintable(lib->errorString));
+            pos = qt_find_pattern(filedata, fdlen, oldPattern, oldPlen);
         }
-        return false;
+    } else if (r == QElfParser::QtMetaDataSection) {
+        long rel = qt_find_pattern(filedata + pos, fdlen, pattern, plen);
+        if (rel < 0)
+            pos = -1;
+        else
+            pos += rel;
+        hasMetaData = true;
     }
 #else
     pos = qt_find_pattern(filedata, fdlen, pattern, plen);
+    if (pos > 0)
+        hasMetaData = true;
+    else
+        pos = qt_find_pattern(filedata, fdlen, oldPattern, oldPlen);
 #endif // defined(Q_OF_ELF) && defined(Q_CC_GNU)
+
     bool ret = false;
-    if (pos >= 0)
-        ret = qt_parse_pattern(filedata + pos, version, debug);
+
+    if (pos >= 0) {
+        if (hasMetaData) {
+            const char *data = filedata + pos;
+            QJsonDocument doc = QLibraryPrivate::fromRawMetaData(data);
+            lib->metaData = doc.object();
+            lib->compatPlugin = false;
+            if (qt_debug_component())
+                qWarning("Found metadata in lib %s, metadata=\n%s\n",
+                         library.toLocal8Bit().constData(), doc.toJson().constData());
+            ret = !doc.isNull();
+        } else {
+            qWarning("Old plugin format found in lib %s", library.toLocal8Bit().constData());
+            uint version;
+            bool isDebug;
+            ret = qt_parse_pattern(filedata + pos, &version, &isDebug);
+            if (ret) {
+                lib->metaData.insert(QLatin1String("version"), (int)version);
+                lib->metaData.insert(QLatin1String("debug"), isDebug);
+                lib->compatPlugin = true;
+            }
+        }
+    }
 
     if (!ret && lib)
         lib->errorString = QLibrary::tr("Plugin verification data mismatch in '%1'").arg(library);
@@ -446,8 +485,9 @@ static LibraryMap *libraryMap()
 }
 
 QLibraryPrivate::QLibraryPrivate(const QString &canonicalFileName, const QString &version)
-    :pHnd(0), fileName(canonicalFileName), fullVersion(version), instance(0), qt_version(0),
-     libraryRefCount(1), libraryUnloadCount(0), pluginState(MightBeAPlugin)
+    : pHnd(0), fileName(canonicalFileName), fullVersion(version), instance(0),
+      compatPlugin(false), loadHints(0),
+      libraryRefCount(1), libraryUnloadCount(0), pluginState(MightBeAPlugin)
 { libraryMap()->insert(canonicalFileName, this); }
 
 QLibraryPrivate *QLibraryPrivate::findOrCreate(const QString &fileName, const QString &version)
@@ -488,6 +528,8 @@ bool QLibraryPrivate::load()
         return false;
 
     bool ret = load_sys();
+    if (qt_debug_component())
+        qDebug() << "loaded library" << fileName;
     if (ret) {
         //when loading a library we add a reference to it so that the QLibraryPrivate won't get deleted
         //this allows to unload the library at a later time
@@ -643,13 +685,33 @@ const char* qt_try_versioninfo(void *pfn, bool *exceptionThrown)
 }
 #endif
 
-#ifdef Q_CC_BOR
-typedef const char * __stdcall (*QtPluginQueryVerificationDataFunction)();
-#else
 typedef const char * (*QtPluginQueryVerificationDataFunction)();
+
+bool qt_get_verificationdata(QtPluginQueryVerificationDataFunction pfn, QLibraryPrivate *priv, bool *exceptionThrown)
+{
+    *exceptionThrown = false;
+    const char *szData = 0;
+    if (!pfn)
+        return false;
+#ifdef QT_USE_MS_STD_EXCEPTION
+    szData = qt_try_versioninfo((void *)pfn, exceptionThrown);
+    if (*exceptionThrown)
+        return false;
+#else
+    szData = pfn();
 #endif
+    uint qt_version;
+    bool debug;
+    if (qt_parse_pattern(szData, &qt_version, &debug)) {
+        priv->metaData.insert(QLatin1String("version"), (int)qt_version);
+        priv->metaData.insert(QLatin1String("debug"), debug);
+        priv->compatPlugin = true;
+        return true;
+    }
+    return false;
+}
 
-bool qt_get_verificationdata(QtPluginQueryVerificationDataFunction pfn, uint *qt_version, bool *debug, bool *exceptionThrown)
+bool qt_get_metadata(QtPluginQueryVerificationDataFunction pfn, QLibraryPrivate *priv, bool *exceptionThrown)
 {
     *exceptionThrown = false;
     const char *szData = 0;
@@ -662,9 +724,17 @@ bool qt_get_verificationdata(QtPluginQueryVerificationDataFunction pfn, uint *qt
 #else
     szData = pfn();
 #endif
-    return qt_parse_pattern(szData, qt_version, debug);
+    if (!szData)
+        return false;
+    QJsonDocument doc = QLibraryPrivate::fromRawMetaData(szData);
+    if (doc.isNull())
+        return false;
+    priv->metaData = doc.object();
+    priv->compatPlugin = false;
+    return true;
 }
 
+
 bool QLibraryPrivate::isPlugin()
 {
     errorString.clear();
@@ -672,7 +742,6 @@ bool QLibraryPrivate::isPlugin()
         return pluginState == IsAPlugin;
 
 #ifndef QT_NO_PLUGIN_CHECK
-    bool debug = !QLIBRARY_AS_DEBUG;
     bool success = false;
 
 #if defined(Q_OS_UNIX) && !defined(Q_OS_MAC)
@@ -692,7 +761,7 @@ bool QLibraryPrivate::isPlugin()
 #if defined(Q_OS_UNIX) && !defined(Q_OS_MAC)
     if (!pHnd) {
         // use unix shortcut to avoid loading the library
-        success = qt_unix_query(fileName, &qt_version, &debug, this);
+        success = qt_unix_query(fileName, this);
     } else
 #endif
     {
@@ -713,24 +782,50 @@ bool QLibraryPrivate::isPlugin()
                 temporary_load =  load_sys();
 #endif
             }
+            QtPluginQueryVerificationDataFunction getMetaData = NULL;
+
+            bool exceptionThrown = false;
+            bool ret = false;
 #ifdef Q_OS_WIN
-            QtPluginQueryVerificationDataFunction qtPluginQueryVerificationDataFunction = hTempModule ? (QtPluginQueryVerificationDataFunction)
+            if (hTempModule) {
+                getMetaData = (QtPluginQueryVerificationDataFunction)
 #ifdef Q_OS_WINCE
-                    ::GetProcAddress(hTempModule, L"qt_plugin_query_verification_data")
+                    ::GetProcAddress(hTempModule, L"qt_plugin_query_metadata")
 #else
-                    ::GetProcAddress(hTempModule, "qt_plugin_query_verification_data")
+                    ::GetProcAddress(hTempModule, "qt_plugin_query_metadata")
+#endif
+                        ;
+            } else
 #endif
-                    : (QtPluginQueryVerificationDataFunction) resolve("qt_plugin_query_verification_data");
+            {
+                getMetaData = (QtPluginQueryVerificationDataFunction) resolve("qt_plugin_query_metadata");
+            }
+
+            if (getMetaData) {
+                ret = qt_get_metadata(getMetaData, this, &exceptionThrown);
+            } else {
+                // try the old plugin style
+                QtPluginQueryVerificationDataFunction qtPluginQueryVerificationDataFunction = NULL;
+#ifdef Q_OS_WIN
+                if (hTempModule) {
+                    qtPluginQueryVerificationDataFunction = (QtPluginQueryVerificationDataFunction)
+#ifdef Q_OS_WINCE
+                        ::GetProcAddress(hTempModule, L"qt_plugin_query_verification_data")
 #else
-            QtPluginQueryVerificationDataFunction qtPluginQueryVerificationDataFunction = NULL;
-            qtPluginQueryVerificationDataFunction = (QtPluginQueryVerificationDataFunction) resolve("qt_plugin_query_verification_data");
+                        ::GetProcAddress(hTempModule, "qt_plugin_query_verification_data")
 #endif
-            bool exceptionThrown = false;
-            bool ret = qt_get_verificationdata(qtPluginQueryVerificationDataFunction,
-                                               &qt_version, &debug, &exceptionThrown);
+                            ;
+                } else
+#endif
+                {
+                    qtPluginQueryVerificationDataFunction = (QtPluginQueryVerificationDataFunction) resolve("qt_plugin_query_verification_data");
+                }
+
+                ret = qt_get_verificationdata(qtPluginQueryVerificationDataFunction, this, &exceptionThrown);
+            }
+
             if (!exceptionThrown) {
                 if (!ret) {
-                    qt_version = 0;
                     if (temporary_load)
                         unload_sys();
                 } else {
@@ -772,6 +867,8 @@ bool QLibraryPrivate::isPlugin()
 
     pluginState = IsNotAPlugin; // be pessimistic
 
+    uint qt_version = (uint)metaData.value(QLatin1String("version")).toDouble();
+    bool debug = metaData.value(QLatin1String("debug")).toBool();
     if ((qt_version & 0x00ff00) > (QT_VERSION & 0x00ff00) || (qt_version & 0xff0000) != (QT_VERSION & 0xff0000)) {
         if (qt_debug_component()) {
             qWarning("In %s:\n"