1 files changed, 281 insertions, 0 deletions
diff --git a/RealtimeSync/monitor.cpp b/RealtimeSync/monitor.cpp
new file mode 100644
index 00000000..88536281
--- /dev/null
+++ b/RealtimeSync/monitor.cpp
@@ -0,0 +1,281 @@
+// **************************************************************************
+// * This file is part of the FreeFileSync project. It is distributed under *
+// * GNU General Public License: http://www.gnu.org/licenses/gpl.html       *
+// * Copyright (C) Zenju (zenju AT gmx DOT de) - All Rights Reserved        *
+// **************************************************************************
+
+#include "monitor.h"
+#include <ctime>
+#include <set>
+#include <zen/file_handling.h>
+#include <zen/dir_watcher.h>
+#include <zen/thread.h>
+#include <zen/tick_count.h>
+#include <wx/utils.h>
+#include "../lib/resolve_path.h"
+//#include "../library/db_file.h"     //SYNC_DB_FILE_ENDING -> complete file too much of a dependency; file ending too little to decouple into single header
+//#include "../library/lock_holder.h" //LOCK_FILE_ENDING
+
+using namespace zen;
+
+
+namespace
+{
+const int CHECK_DIR_INTERVAL = 1; //unit: [s]
+
+
+std::vector<Zstring> getFormattedDirs(const std::vector<Zstring>& dirs) //throw FileError
+{
+    std::set<Zstring, LessFilename> tmp; //make unique
+
+    std::transform(dirs.begin(), dirs.end(), std::inserter(tmp, tmp.end()),
+    [](const Zstring& dirnameNonFmt) { return getFormattedDirectoryName(dirnameNonFmt); });
+
+    return std::vector<Zstring>(tmp.begin(), tmp.end());
+}
+
+
+//wait until changes are detected or if a directory is not available (anymore)
+struct WaitResult
+{
+    enum ChangeType
+    {
+        CHANGE_DETECTED,
+        CHANGE_DIR_MISSING
+    };
+
+    WaitResult(const zen::DirWatcher::Entry& changedItem) : type(CHANGE_DETECTED), changedItem_(changedItem) {}
+    WaitResult(const Zstring& dirname) : type(CHANGE_DIR_MISSING), dirname_(dirname) {}
+
+    ChangeType type;
+    zen::DirWatcher::Entry changedItem_; //for type == CHANGE_DETECTED: file or directory
+    Zstring dirname_;                    //for type == CHANGE_DIR_MISSING
+};
+
+
+WaitResult waitForChanges(const std::vector<Zstring>& dirNamesNonFmt, //throw FileError
+                          const std::function<void(bool)>& onRefreshGui)  //bool: readyForSync
+{
+    const std::vector<Zstring> dirNamesFmt = getFormattedDirs(dirNamesNonFmt); //throw FileError
+    if (dirNamesFmt.empty()) //pathological case, but we have to check else this function will wait endlessly
+        throw zen::FileError(_("A folder input field is empty.")); //should have been checked by caller!
+
+    //detect when volumes are removed/are not available anymore
+    std::vector<std::pair<Zstring, std::shared_ptr<DirWatcher>>> watches;
+
+    for (auto it = dirNamesFmt.begin(); it != dirNamesFmt.end(); ++it)
+    {
+        const Zstring& dirnameFmt = *it;
+        try
+        {
+            //a non-existent network path may block, so check existence asynchronously!
+            auto ftDirExists = async([=] { return zen::dirExists(dirnameFmt); });
+            //we need to check dirExists(), not somethingExists(): it's not clear if DirWatcher detects a type clash (file instead of directory!)
+            while (!ftDirExists.timed_wait(boost::posix_time::milliseconds(rts::UI_UPDATE_INTERVAL / 2)))
+                onRefreshGui(false); //may throw!
+            if (!ftDirExists.get())
+                return WaitResult(dirnameFmt);
+
+            watches.push_back(std::make_pair(dirnameFmt, std::make_shared<DirWatcher>(dirnameFmt))); //throw FileError
+        }
+        catch (FileError&)
+        {
+            if (!somethingExists(dirnameFmt)) //a benign(?) race condition with FileError
+                return WaitResult(dirnameFmt);
+            throw;
+        }
+    }
+
+    const std::int64_t TICKS_DIR_CHECK_INTERVAL = CHECK_DIR_INTERVAL * ticksPerSec(); //0 on error
+    TickVal lastCheck = getTicks(); //0 on error
+    while (true)
+    {
+        const bool checkDirExistNow = [&]() -> bool //checking once per sec should suffice
+        {
+            const TickVal now = getTicks(); //0 on error
+            if (dist(lastCheck, now) >= TICKS_DIR_CHECK_INTERVAL)
+            {
+                lastCheck = now;
+                return true;
+            }
+            return false;
+        }();
+
+
+        for (auto it = watches.begin(); it != watches.end(); ++it)
+        {
+            const Zstring& dirname = it->first;
+            DirWatcher& watcher = *(it->second);
+
+            //IMPORTANT CHECK: dirwatcher has problems detecting removal of top watched directories!
+            if (checkDirExistNow)
+                if (!dirExists(dirname)) //catch errors related to directory removal, e.g. ERROR_NETNAME_DELETED -> somethingExists() is NOT sufficient here!
+                    return WaitResult(dirname);
+            try
+            {
+                std::vector<DirWatcher::Entry> changedItems = watcher.getChanges([&] { onRefreshGui(false); /*may throw!*/ }); //throw FileError
+
+                //remove to be ignored changes
+                vector_remove_if(changedItems, [](const DirWatcher::Entry& e)
+                {
+                    return endsWith(e.filename_, Zstr(".ffs_lock")) || //sync.ffs_lock, sync.Del.ffs_lock
+                           endsWith(e.filename_, Zstr(".ffs_db"));     //sync.ffs_db, .sync.tmp.ffs_db
+                    //no need to ignore temporal recycle bin directory: this must be caused by a file deletion anyway
+                });
+
+                if (!changedItems.empty())
+                {
+                    /*
+                                    std::for_each(changedItems.begin(), changedItems.end(),
+                                    [](const Zstring& fn) { wxMessageBox(toWx(fn));});
+                    */
+                    return WaitResult(changedItems[0]); //directory change detected
+                }
+
+            }
+            catch (FileError&)
+            {
+                if (!somethingExists(dirname)) //a benign(?) race condition with FileError
+                    return WaitResult(dirname);
+                throw;
+            }
+        }
+
+        boost::this_thread::sleep(boost::posix_time::milliseconds(rts::UI_UPDATE_INTERVAL / 2));
+        onRefreshGui(true); //throw ?: may start sync at this presumably idle time
+    }
+}
+
+
+//wait until all directories become available (again) + logs in network share
+void waitForMissingDirs(const std::vector<Zstring>& dirNamesNonFmt, //throw FileError
+                        const std::function<void(const Zstring&)>& onRefreshGui) //Zstring: the directory that is currently being waited for
+{
+    while (true)
+    {
+        //support specifying volume by name => call getFormattedDirectoryName() repeatedly
+        const std::vector<Zstring>& dirNamesFmt = getFormattedDirs(dirNamesNonFmt); //throw FileError
+
+        bool allExisting = true;
+        for (auto it = dirNamesFmt.begin(); it != dirNamesFmt.end(); ++it)
+        {
+            const Zstring dirnameFmt = *it;
+            auto ftDirExisting = async([=]() -> bool
+            {
+#ifdef ZEN_WIN
+                //1. login to network share, if necessary -> we probably do NOT want multiple concurrent runs: GUI!?
+                loginNetworkShare(dirnameFmt, false); //login networks shares, no PW prompt -> is this really RTS's job?
+#endif
+                //2. check dir existence
+                return zen::dirExists(dirnameFmt);
+            });
+            while (!ftDirExisting.timed_wait(boost::posix_time::milliseconds(rts::UI_UPDATE_INTERVAL / 2)))
+                onRefreshGui(dirnameFmt); //may throw!
+
+            if (!ftDirExisting.get())
+            {
+                allExisting = false;
+                //wait some time...
+                const int refreshInterval = rts::UI_UPDATE_INTERVAL / 2;
+                assert_static(CHECK_DIR_INTERVAL * 1000 % refreshInterval == 0);
+                for (int i = 0; i < CHECK_DIR_INTERVAL * 1000 / refreshInterval; ++i)
+                {
+                    onRefreshGui(dirnameFmt); //may throw!
+                    boost::this_thread::sleep(boost::posix_time::milliseconds(refreshInterval));
+                }
+                break;
+            }
+        }
+        if (allExisting)
+            return;
+    }
+}
+
+
+inline
+wxString toString(DirWatcher::ActionType type)
+{
+    switch (type)
+    {
+        case DirWatcher::ACTION_CREATE:
+            return L"CREATE";
+        case DirWatcher::ACTION_UPDATE:
+            return L"UPDATE";
+        case DirWatcher::ACTION_DELETE:
+            return L"DELETE";
+    }
+    return L"ERROR";
+}
+
+struct ExecCommandNowException {};
+}
+
+
+void rts::monitorDirectories(const std::vector<Zstring>& dirNamesNonFmt, unsigned int delay, rts::MonitorCallback& callback)
+{
+    if (dirNamesNonFmt.empty())
+    {
+        assert(false);
+        return;
+    }
+
+    auto execMonitoring = [&] //throw FileError
+    {
+        callback.setPhase(MonitorCallback::MONITOR_PHASE_WAITING);
+        waitForMissingDirs(dirNamesNonFmt, [&](const Zstring& dirname) { callback.requestUiRefresh(); }); //throw FileError
+        callback.setPhase(MonitorCallback::MONITOR_PHASE_ACTIVE);
+
+        //schedule initial execution (*after* all directories have arrived, which could take some time which we don't want to include)
+        time_t nextExecDate = std::time(nullptr) + delay;
+
+        while (true) //loop over command invocations
+        {
+            DirWatcher::Entry lastChangeDetected;
+            try
+            {
+                while (true) //loop over detected changes
+                {
+                    //wait for changes (and for all directories to become available)
+                    WaitResult res = waitForChanges(dirNamesNonFmt, [&](bool readyForSync) //throw FileError, ExecCommandNowException
+                    {
+                        if (readyForSync)
+                            if (nextExecDate <= std::time(nullptr))
+                                throw ExecCommandNowException(); //abort wait and start sync
+                        callback.requestUiRefresh();
+                    });
+                    switch (res.type)
+                    {
+                        case WaitResult::CHANGE_DIR_MISSING: //don't execute the command before all directories are available!
+                            callback.setPhase(MonitorCallback::MONITOR_PHASE_WAITING);
+                            waitForMissingDirs(dirNamesNonFmt, [&](const Zstring& dirname) { callback.requestUiRefresh(); }); //throw FileError
+                            callback.setPhase(MonitorCallback::MONITOR_PHASE_ACTIVE);
+                            break;
+
+                        case WaitResult::CHANGE_DETECTED:
+                            lastChangeDetected = res.changedItem_;
+                            break;
+                    }
+                    nextExecDate = std::time(nullptr) + delay;
+                }
+            }
+            catch (ExecCommandNowException&) {}
+
+            ::wxSetEnv(L"change_path", utfCvrtTo<wxString>(lastChangeDetected.filename_)); //some way to output what file changed to the user
+            ::wxSetEnv(L"change_action", toString(lastChangeDetected.action_)); //
+
+            //execute command
+            callback.executeExternalCommand();
+            nextExecDate = std::numeric_limits<time_t>::max();
+        }
+    };
+
+    while (true)
+        try
+        {
+            execMonitoring(); //throw FileError
+        }
+        catch (const zen::FileError& e)
+        {
+            callback.reportError(e.toString());
+        }
+}