WebDAV: allow compilation on older distros (Ubuntu Hardy)

libneon 0.27 doesn't have ne_options2() and
ne_session_system_proxy(). ne_options2() is purely for debugging,
disabled in builds on old distros. ne_session_system_proxy() is needed
to enable the use of the system proxy settings. If a recent enough
libneon.so.27 is found at runtime (= one which has the function), then
it is called.

libical was contained in libecal in Ubuntu Hardy, at least the way how
SyncEvolution is compiled there. Thus use libecal-1.2 when libical is
not found. Also handle the different ical string allocation semantic
via the icalstrdup() wrapper.

src/backends/webdav/CalDAVSource.cpp

@@ -2,18 +2,21 @@
  * Copyright (C) 2010 Intel Corporation
  */
 
-#include "CalDAVSource.h"
+#include "config.h"
 
 #ifdef ENABLE_DAV
 
+// include first, it sets HANDLE_LIBICAL_MEMORY for us
+#include <syncevo/icalstrdup.h>
+
+#include "CalDAVSource.h"
+
 #include <boost/bind.hpp>
 #include <boost/algorithm/string/replace.hpp>
 
 #include <syncevo/declarations.h>
 SE_BEGIN_CXX
 
-// TODO: use EDS backend icalstrdup.c
-#define ical_strdup(_x) (_x)
 
 CalDAVSource::CalDAVSource(const SyncSourceParams &params,
                            const boost::shared_ptr<Neon::Settings> &settings) :
@@ -83,7 +86,7 @@ int CalDAVSource::appendItem(SubRevisionMap_t &revisions,
                              std::string &data)
 {
     Event::unescapeRecurrenceID(data);
-    eptr<icalcomponent> calendar(icalcomponent_new_from_string(data.c_str()),
+    eptr<icalcomponent> calendar(icalcomponent_new_from_string((char *)data.c_str()), // cast is a hack for broken definition in old libical
                                  "iCalendar 2.0");
     std::string davLUID = path2luid(Neon::URI::parse(href).m_path);
     pair<string, set<string> > &rev = revisions[davLUID];
@@ -614,7 +617,7 @@ CalDAVSource::Event &CalDAVSource::loadItem(Event &event)
             }
         }
         Event::unescapeRecurrenceID(item);
-        event.m_calendar.set(icalcomponent_new_from_string(item.c_str()),
+        event.m_calendar.set(icalcomponent_new_from_string((char *)item.c_str()), // hack for old libical
                              "parsing iCalendar 2.0");
         // sequence number might have been increased by last save,
         // so check it again

src/backends/webdav/NeonCXX.cpp

@@ -21,6 +21,8 @@
 #include <syncevo/LogRedirect.h>
 #include <syncevo/SmartPtr.h>
 
+#include <dlfcn.h>
+
 #include <syncevo/declarations.h>
 SE_BEGIN_CXX
 
@@ -196,7 +198,18 @@ Session::Session(const boost::shared_ptr<Settings> &settings) :
 
     m_proxyURL = settings->proxy();
     if (m_proxyURL.empty()) {
+#ifdef HAVE_LIBNEON_SYSTEM_PROXY
+        // hard compile-time dependency
         ne_session_system_proxy(m_session, 0);
+#else
+        // compiled against older libneon, but might run with more recent neon
+        typedef void (*session_system_proxy_t)(ne_session *sess, unsigned int flags);
+        session_system_proxy_t session_system_proxy =
+            (session_system_proxy_t)dlsym(RTLD_DEFAULT, "ne_session_system_proxy");
+        if (session_system_proxy) {
+            session_system_proxy(m_session, 0);
+        }
+#endif
     } else {
         URI proxyuri = URI::parse(m_proxyURL);
         ne_session_proxy(m_session, proxyuri.m_host.c_str(), proxyuri.m_port);
@@ -317,12 +330,14 @@ int Session::sslVerify(void *userdata, int failures, const ne_ssl_certificate *c
     }
 }
 
+#ifdef HAVE_LIBNEON_OPTIONS
 unsigned int Session::options(const std::string &path)
 {
     unsigned int caps;
     check(ne_options2(m_session, path.c_str(), &caps));
     return caps;
 }
+#endif // HAVE_LIBNEON_OPTIONS
 
 void Session::propfindURI(const std::string &path, int depth,
                           const ne_propname *props,

src/backends/webdav/NeonCXX.h

@@ -181,8 +181,10 @@ class Session {
     static boost::shared_ptr<Session> create(const boost::shared_ptr<Settings> &settings);
     ~Session();
 
+#ifdef HAVE_LIBNEON_OPTIONS
     /** ne_options2() for a specific path*/
     unsigned int options(const std::string &path);
+#endif
 
     /**
      * called with URI and complete result set; exceptions are logged, but ignored

src/backends/webdav/WebDAVSource.cpp

@@ -540,6 +540,7 @@ void WebDAVSource::open()
     SE_LOG_DEBUG(NULL, NULL, "picked final path %s", m_calendar.m_path.c_str());
 
     // Check some server capabilities. Purely informational at this point.
+#ifdef HAVE_LIBNEON_OPTIONS
     if (LoggerBase::instance().getLevel() >= Logger::DEV) {
         SE_LOG_DEBUG(NULL, NULL, "read capabilities of %s", m_calendar.toURL().c_str());
         int caps = m_session->options(path);
@@ -566,6 +567,7 @@ void WebDAVSource::open()
                      m_session->getURL().c_str(),
                      Flags2String(caps, descr).c_str());
     }
+#endif // HAVE_LIBNEON_OPTIONS
 }
 
 void WebDAVSource::openPropCallback(const Neon::URI &uri,

src/backends/webdav/configure-sub.in

@@ -10,9 +10,15 @@ AC_ARG_ENABLE_BACKEND(dav,
                       )
 
 if test "$enable_dav" = "yes"; then
-        PKG_CHECK_MODULES(LIBICAL, libical)
-        PKG_CHECK_MODULES(NEON, neon >= 0.29)
+        PKG_CHECK_MODULES(LIBICAL, libical,
+                          [true],
+                          [PKG_CHECK_MODULES(LIBICAL, libecal-1.2)])
+        PKG_CHECK_MODULES(NEON, neon >= 0.29,
+                          [AC_DEFINE(HAVE_LIBNEON_SYSTEM_PROXY, 1, [ne_session_system_proxy() available])
+                           AC_DEFINE(HAVE_LIBNEON_OPTIONS, 1, [ne_options2() and NE_CAP_* defines available])],
+                          [PKG_CHECK_MODULES(NEON, neon >= 0.27)])
         AC_DEFINE(ENABLE_DAV, 1, [DAV available])
         AC_DEFINE(ENABLE_ICAL, 1, [libical in use])
         BACKEND_CPPFLAGS="$BACKEND_CPPFLAGS $NEON_CFLAGS"
 fi
+AM_CONDITIONAL([ENABLE_ICAL], [test "$enable_dav" = "yes"])