added new functiion pluginPaths

Retrieve plugin paths. It consists of:
1. QCA_PLUGIN_PATH environment if set.
2. QCoreApplication::libraryPaths() .
3. Directory where plugins were installed.

QCA_PLUGIN_PATH is paths list like PATH or QT_PLUGIN_PATH.
It uses system path separator. ";" on Windows and ":" on Unix.

Also qcatool now uses this function.

CMakeLists.txt

@@ -89,10 +89,6 @@ else(QCA_SUFFIX)
   set(QCA_PC_NAME qca2.pc)
 endif(QCA_SUFFIX)
 
-if(DEVELOPER_MODE)
-  add_definitions(-DDEVELOPER_MODE -DQCA_PLUGIN_PATH="${CMAKE_BINARY_DIR}/lib/${QCA_LIB_NAME}")
-endif(DEVELOPER_MODE)
-
 set(QCA_LIB_VERSION_STRING "${QCA_LIB_MAJOR_VERSION}.${QCA_LIB_MINOR_VERSION}.${QCA_LIB_PATCH_VERSION}")
 
 configure_file("include/QtCrypto/qca_version.h.in" "${CMAKE_BINARY_DIR}/qca_version.h")
@@ -222,6 +218,12 @@ else()
   set(QCA_PREFIX_INSTALL_DIR "")
 endif()
 
+if(DEVELOPER_MODE)
+  add_definitions(-DDEVELOPER_MODE -DQCA_PLUGIN_PATH="${CMAKE_BINARY_DIR}/lib/${QCA_LIB_NAME}")
+else()
+  add_definitions(-DQCA_PLUGIN_PATH="${QCA_PREFIX_INSTALL_DIR}${QCA_PLUGINS_INSTALL_DIR}")
+endif(DEVELOPER_MODE)
+
 if (APPLE)
    find_package(Carbon REQUIRED)
    set(CMAKE_INSTALL_NAME_DIR ${QCA_LIBRARY_INSTALL_DIR})

include/QtCrypto/qca_core.h

@@ -369,6 +369,19 @@ QCA_EXPORT Provider *findProvider(const QString &name);
 */
 QCA_EXPORT Provider *defaultProvider();
 
+/**
+   Retrieve plugin paths. It consists of:
+   1. QCA_PLUGIN_PATH environment if set.
+   2. \c %QCoreApplication::libraryPaths() .
+   3. Directory where plugins were installed.
+
+   QCA_PLUGIN_PATH is paths list like PATH or QT_PLUGIN_PATH.
+   It uses system path separator. \";\" on Windows and \":\" on Unix.
+
+   This function was introduced in %QCA 2.1.
+*/
+QCA_EXPORT QStringList pluginPaths();
+
 /**
    Scan for new plugins
 */

src/qca_core.cpp

@@ -34,6 +34,7 @@
 #include <QSettings>
 #include <QVariantMap>
 #include <QWaitCondition>
+#include <QDir>
 
 #ifdef Q_OS_UNIX
 # include <unistd.h>
@@ -452,6 +453,37 @@ Provider *defaultProvider()
 	return global->manager->find("default");
 }
 
+QStringList pluginPaths()
+{
+	QStringList paths;
+#ifndef DEVELOPER_MODE
+	const QString qcaPluginPath = qgetenv("QCA_PLUGIN_PATH");
+	if (!qcaPluginPath.isEmpty())
+	{
+#ifdef Q_OS_WIN
+		QLatin1Char pathSep(';');
+#else
+		QLatin1Char pathSep(':');
+#endif
+		foreach (const QString &path, qcaPluginPath.split(pathSep))
+		{
+			QString canonicalPath = QDir(path).canonicalPath();
+			if (!canonicalPath.isEmpty())
+				paths << canonicalPath;
+		}
+
+	}
+	paths += QCoreApplication::libraryPaths();
+#endif
+	// In developer mode load plugins only from buildtree.
+	// In regular mode QCA_PLUGIN_PATH is path where plugins was installed
+	paths << QDir(QCA_PLUGIN_PATH).canonicalPath();
+#ifndef DEVELOPER_MODE
+	paths.removeDuplicates();
+#endif
+	return paths;
+}
+
 void scanForPlugins()
 {
 	if(!global_check_load())

src/qca_plugin.cpp

@@ -366,14 +366,7 @@ void ProviderManager::scan()
 	if(qgetenv("QCA_NO_PLUGINS") == "1")
 		return;
 
-	// check plugin files
-#ifdef DEVELOPER_MODE
-	// Load plugins only from buildtree
-	QStringList dirs;
-	dirs << QCA_PLUGIN_PATH;
-#else
-	const QStringList dirs = QCoreApplication::libraryPaths();
-#endif
+	const QStringList dirs = pluginPaths();
 	if(dirs.isEmpty())
 		logDebug("No Qt Library Paths");
 	for(QStringList::ConstIterator it = dirs.begin(); it != dirs.end(); ++it)

tools/qcatool/main.cpp

@@ -2881,14 +2881,7 @@ int main(int argc, char **argv)
 	// show plugins
 	if(args[0] == "plugins")
 	{
-#ifdef DEVELOPER_MODE
-		printf("QCA build tree path:\n");
-		QStringList paths;
-		paths << QCA_PLUGIN_PATH;
-#else
-		printf("Qt Library Paths:\n");
-		QStringList paths = QCoreApplication::libraryPaths();
-#endif
+		QStringList paths = QCA::pluginPaths();
 		if(!paths.isEmpty())
 		{
 			for(int n = 0; n < paths.count(); ++n)