1 files changed, 37 insertions, 30 deletions

diff --git a/lib/lock_holder.h b/lib/lock_holder.h
index 6265747b..5ae2f8ae 100644
--- a/lib/lock_holder.h
+++ b/lib/lock_holder.h
@@ -3,6 +3,7 @@
 
 #include <map>
 #include <zen/zstring.h>
+#include <zen/stl_tools.h>
 #include "dir_lock.h"
 #include "status_handler.h"
 #include "dir_exist_async.h"
@@ -11,43 +12,49 @@ namespace zen
 {
 const Zstring LOCK_FILE_ENDING = Zstr(".ffs_lock"); //intermediate locks created by DirLock use this extension, too!
 
-//convenience class for creating and holding locks for a number of directories
+//hold locks for a number of directories without blocking during lock creation
 class LockHolder
 {
 public:
-    LockHolder(bool allowUserInteraction) : allowUserInteraction_(allowUserInteraction) {}
-
-    void addDir(const Zstring& dirnameFmt, ProcessCallback& procCallback) //resolved dirname ending with path separator
+    LockHolder(const std::vector<Zstring>& dirnamesFmt, //resolved dirname ending with path separator
+               ProcessCallback& procCallback,
+               bool allowUserInteraction) : allowUserInteraction_(allowUserInteraction)
     {
-        if (dirnameFmt.empty())
-            return;
+        std::vector<Zstring> dirs = dirnamesFmt;
+        vector_remove_if(dirs, [](const Zstring& dir) { return dir.empty(); });
 
-        if (!dirExistsUpdating(dirnameFmt, allowUserInteraction_, procCallback))
-            return;
+        for (auto iter = dirs.begin(); iter != dirs.end(); ++iter)
+        {
+            const Zstring& dirnameFmt = *iter;
 
-        if (lockHolder.find(dirnameFmt) != lockHolder.end()) return;
-        assert(endsWith(dirnameFmt, FILE_NAME_SEPARATOR)); //this is really the contract, formatting does other things as well, e.g. macro substitution
+            if (!dirExistsUpdating(dirnameFmt, allowUserInteraction_, procCallback))
+                continue;
 
-        class WaitOnLockHandler : public DirLockCallback
-        {
-        public:
-            WaitOnLockHandler(ProcessCallback& pc) : pc_(pc) {}
-            virtual void requestUiRefresh() { pc_.requestUiRefresh(); }  //allowed to throw exceptions
-            virtual void reportInfo(const std::wstring& text) { pc_.reportStatus(text); }
-        private:
-            ProcessCallback& pc_;
-        } callback(procCallback);
-
-        try
-        {
-            //lock file creation is synchronous and may block noticably for very slow devices (usb sticks, mapped cloud storages)
-            procCallback.forceUiRefresh(); //=> make sure the right folder name is shown on GUI during this time!
-            lockHolder.insert(std::make_pair(dirnameFmt, DirLock(dirnameFmt + Zstr("sync") + LOCK_FILE_ENDING, &callback)));
-        }
-        catch (const FileError& e)
-        {
-            bool dummy = false; //this warning shall not be shown but logged only
-            procCallback.reportWarning(e.toString(), dummy); //may throw!
+            if (lockHolder.find(dirnameFmt) != lockHolder.end())
+                continue;
+            assert(endsWith(dirnameFmt, FILE_NAME_SEPARATOR)); //this is really the contract, formatting does other things as well, e.g. macro substitution
+
+            class WaitOnLockHandler : public DirLockCallback
+            {
+            public:
+                WaitOnLockHandler(ProcessCallback& pc) : pc_(pc) {}
+                virtual void requestUiRefresh() { pc_.requestUiRefresh(); }  //allowed to throw exceptions
+                virtual void reportInfo(const std::wstring& text) { pc_.reportStatus(text); }
+            private:
+                ProcessCallback& pc_;
+            } callback(procCallback);
+
+            try
+            {
+                //lock file creation is synchronous and may block noticably for very slow devices (usb sticks, mapped cloud storages)
+                procCallback.forceUiRefresh(); //=> make sure the right folder name is shown on GUI during this time!
+                lockHolder.insert(std::make_pair(dirnameFmt, DirLock(dirnameFmt + Zstr("sync") + LOCK_FILE_ENDING, &callback)));
+            }
+            catch (const FileError& e)
+            {
+                bool dummy = false; //this warning shall not be shown but logged only
+                procCallback.reportWarning(e.toString(), dummy); //may throw!
+            }
         }
     }