From 46e3aa29081e0c043d745e590b9d3b9220f8d471 Mon Sep 17 00:00:00 2001
From: Lars Knoll <lars.knoll@nokia.com>
Date: Fri, 20 Jul 2012 20:49:13 +0200
Subject: Lazily initialize iconv in the iconv codec

Avoid dlopen'ing libiconv and initializing
it's members until the codec gets used for
the first time. This avoids some memory
and startup time overhead in case we can
use the utf8 codec instead of iconv.

It also removes a circular dependency
between codec initialization during app
startup.

Change-Id: I119c010c288dc59ab32279d8a213ae1f4347cace
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
---
 src/corelib/codecs/qiconvcodec.cpp | 13 ++++++++++---
 src/corelib/codecs/qiconvcodec_p.h |  3 ++-
 2 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/src/corelib/codecs/qiconvcodec.cpp b/src/corelib/codecs/qiconvcodec.cpp
index c7c1d365b6..e56f8885e7 100644
--- a/src/corelib/codecs/qiconvcodec.cpp
+++ b/src/corelib/codecs/qiconvcodec.cpp
@@ -92,6 +92,10 @@ QT_BEGIN_NAMESPACE
 
 QIconvCodec::QIconvCodec()
     : utf16Codec(0)
+{
+}
+
+void QIconvCodec::init() const
 {
     utf16Codec = QTextCodec::codecForMib(1015);
     Q_ASSERT_X(utf16Codec != 0,
@@ -203,7 +207,7 @@ QString QIconvCodec::convertToUnicode(const char* chars, int len, ConverterState
 
     if (!*pstate) {
         // first time, create the state
-        iconv_t cd = QIconvCodec::createIconv_t(UTF16, 0);
+        iconv_t cd = createIconv_t(UTF16, 0);
         if (cd == reinterpret_cast<iconv_t>(-1)) {
             static int reported = 0;
             if (!reported++) {
@@ -348,7 +352,7 @@ QByteArray QIconvCodec::convertFromUnicode(const QChar *uc, int len, ConverterSt
     QThreadStorage<QIconvCodec::IconvState *> *ts = fromUnicodeState();
     IconvState *&state = ts ? ts->localData() : temporaryState;
     if (!state) {
-        iconv_t cd = QIconvCodec::createIconv_t(0, UTF16);
+        iconv_t cd = createIconv_t(0, UTF16);
         if (cd != reinterpret_cast<iconv_t>(-1)) {
             if (!setByteOrder(cd)) {
                 perror("QIconvCodec::convertFromUnicode: using Latin-1 for conversion, iconv failed for BOM");
@@ -460,10 +464,13 @@ int QIconvCodec::mibEnum() const
     return 0;
 }
 
-iconv_t QIconvCodec::createIconv_t(const char *to, const char *from)
+iconv_t QIconvCodec::createIconv_t(const char *to, const char *from) const
 {
     Q_ASSERT((to == 0 && from != 0) || (to != 0 && from == 0));
 
+    if (!utf16Codec)
+        init();
+
     iconv_t cd = (iconv_t) -1;
 #if defined(__GLIBC__) || defined(GNU_LIBICONV) || defined(Q_OS_QNX)
 #if defined(Q_OS_QNX)
diff --git a/src/corelib/codecs/qiconvcodec_p.h b/src/corelib/codecs/qiconvcodec_p.h
index efe3b4b5f7..4b8bc68603 100644
--- a/src/corelib/codecs/qiconvcodec_p.h
+++ b/src/corelib/codecs/qiconvcodec_p.h
@@ -80,7 +80,8 @@ public:
     QByteArray name() const;
     int mibEnum() const;
 
-    static iconv_t createIconv_t(const char *to, const char *from);
+    void init() const;
+    iconv_t createIconv_t(const char *to, const char *from) const;
 
     class IconvState
     {
-- 
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