Added download slots and automatic download cancellation after a delay

PBMap.pb

@@ -125,6 +125,7 @@ Module PBMap
     CacheFile.s
     GetImageThread.i
     Download.i
+    Time.i
   EndStructure
   
   Structure BoundingBox 
@@ -198,6 +199,7 @@ Module PBMap
     TimerInterval.i
     MaxMemCache.i                                  ; in MiB
     MaxThreads.i                                   ; Maximum simultaneous web loading threads
+    MaxDownloadSlots.i                             ; Maximum simultaneous download slots
     TileLifetime.i
     Verbose.i                                      ; Maximum debug informations
     Warning.i                                      ; Warning requesters
@@ -288,7 +290,10 @@ Module PBMap
     Redraw.i
     Dragging.i
     Dirty.i                                        ; To signal that drawing need a refresh
+    
     MemoryCacheManagement.i                        ; To pause web loading threads    
+    DownloadSlots.i                                ; Actual nb of used download slots
+    DownloadSlotsMutex.i                           ; To be sure that only one thread at a time can access to the DownloadSlots var
 
     List TracksList.Tracks()                       ; To display a GPX track
     List Markers.Marker()                          ; To diplay marker
@@ -687,6 +692,8 @@ Module PBMap
         PBMap\Options\MaxMemCache = Val(Value)
       Case "maxthreads"
         PBMap\Options\MaxThreads = Val(Value)
+      Case "maxdownloadslots"
+        PBMap\Options\MaxDownloadSlots = Val(Value)
       Case "tilelifetime"
         PBMap\Options\TileLifetime =  Val(Value)
       Case "verbose"
@@ -756,6 +763,8 @@ Module PBMap
           ProcedureReturn StrU(\MaxMemCache)
         Case "maxthreads"
           ProcedureReturn StrU(\MaxThreads)
+        Case "maxdownloadslots"
+          ProcedureReturn StrU(\MaxDownloadSlots)
         Case "tilelifetime"
           ProcedureReturn StrU(\TileLifetime)  
         Case "verbose"
@@ -818,6 +827,7 @@ Module PBMap
       WritePreferenceInteger("WheelMouseRelative", \WheelMouseRelative)
       WritePreferenceInteger("MaxMemCache", \MaxMemCache)
       WritePreferenceInteger("MaxThreads", \MaxThreads)
+      WritePreferenceInteger("MaxDownloadSlots", \MaxDownloadSlots)
       WritePreferenceInteger("TileLifetime", \TileLifetime)  
       WritePreferenceInteger("Verbose", \Verbose)
       WritePreferenceInteger("Warning", \Warning)
@@ -882,7 +892,8 @@ Module PBMap
       PreferenceGroup("OPTIONS")   
       \WheelMouseRelative = ReadPreferenceInteger("WheelMouseRelative", #True)
       \MaxMemCache        = ReadPreferenceInteger("MaxMemCache", 20480) ; 20 MiB, about 80 tiles in memory
-      \MaxThreads         = ReadPreferenceInteger("MaxThreads", 10)
+      \MaxThreads         = ReadPreferenceInteger("MaxThreads", 40)
+      \MaxDownloadSlots   = ReadPreferenceInteger("MaxDownloadSlots", 2)
       \TileLifetime       = ReadPreferenceInteger("TileLifetime", 1209600) ; about 2 weeks ;-1 = unlimited
       \Verbose            = ReadPreferenceInteger("Verbose", #False)
       \Warning            = ReadPreferenceInteger("Warning", #False)
@@ -1031,6 +1042,8 @@ Module PBMap
     ProcedureReturn PBMap\Layers(Name)\Alpha
   EndProcedure
   
+  ;-***
+  
   Procedure MemoryCacheManagement()
     ; If cache size exceeds limit, try to delete the oldest tiles used (first in the time stack)
     Protected CacheSize = MapSize(PBMap\MemCache\Images()) * Pow(PBMap\TileSize, 2) * 5 ; Size of a tile = TileSize * TileSize * 4 bytes (RGBA) 
@@ -1133,6 +1146,20 @@ Module PBMap
   
   Procedure GetImageThread(*Tile.Tile)
     MyDebug("Thread starting for image " + *Tile\CacheFile + "(" + *Tile\key + ")", 5)
+    ; Waits for a free download slot
+    LockMutex(PBMap\DownloadSlotsMutex)
+    While PBMap\DownloadSlots >= PBMap\Options\MaxDownloadSlots      
+      UnlockMutex(PBMap\DownloadSlotsMutex)
+      If ElapsedMilliseconds() - *Tile\Time > 10000
+        MyDebug(" Thread for image " + *Tile\CacheFile + " canceled after 10 seconds waiting for a slot.", 5)
+        PostEvent(#PB_Event_Gadget, PBMap\Window, PBmap\Gadget, #PB_MAP_TILE_CLEANUP, *Tile) ; To free memory outside the thread
+        ProcedureReturn #False
+      EndIf
+      Delay(500)
+      LockMutex(PBMap\DownloadSlotsMutex)
+    Wend
+    PBMap\DownloadSlots + 1
+    UnlockMutex(PBMap\DownloadSlotsMutex)
     *Tile\Download = ReceiveHTTPFile(*Tile\URL, *Tile\CacheFile, #PB_HTTP_Asynchronous)
     If *Tile\Download
       Repeat
@@ -1143,22 +1170,23 @@ Module PBMap
               Size = FinishHTTP(*Tile\Download)
               MyDebug(" Thread for image " + *Tile\CacheFile + " finished. Size : " + Str(Size), 5)
               PostEvent(#PB_Event_Gadget, PBMap\Window, PBmap\Gadget, #PB_MAP_TILE_CLEANUP, *Tile) ; To free memory outside the thread
-              *Tile\Download = 0
               ProcedureReturn #True
             Case #PB_Http_Failed
               FinishHTTP(*Tile\Download)
               MyDebug(" Thread for image " + *Tile\CacheFile + " failed.", 5)
               PostEvent(#PB_Event_Gadget, PBMap\Window, PBmap\Gadget, #PB_MAP_TILE_CLEANUP, *Tile) ; To free memory outside the thread
-              *Tile\Download = 0
               ProcedureReturn #False
             Case #PB_Http_Aborted
               FinishHTTP(*Tile\Download)
               MyDebug(" Thread for image " + *Tile\CacheFile + " aborted.", 5)
               PostEvent(#PB_Event_Gadget, PBMap\Window, PBmap\Gadget, #PB_MAP_TILE_CLEANUP, *Tile) ; To free memory outside the thread
-              *Tile\Download = 0
               ProcedureReturn #False
             Default
               MyDebug(" Thread for image " + *Tile\CacheFile + " downloading " + Str(Progress) + " bytes", 5)
+              If ElapsedMilliseconds() - *Tile\Time > 60000
+                MyDebug(" Thread for image " + *Tile\CacheFile + " canceled after 60 seconds.", 5)
+                AbortHTTP(*Tile\Download)
+              EndIf
           EndSelect
         EndIf
         Delay(500) ; Frees CPU
@@ -1227,6 +1255,7 @@ Module PBMap
             \URL = URL
             \CacheFile = CacheFile
             \nImage = 0 
+            \Time = ElapsedMilliseconds()
             \GetImageThread = CreateThread(@GetImageThread(), *NewTile)
             If \GetImageThread
               MyDebug(" Creating get image thread nb " + Str(\GetImageThread) + " to get " + CacheFile, 3)
@@ -2281,7 +2310,7 @@ Module PBMap
       Case #PB_EventType_LeftButtonDown
         ; LatLon2Pixel(@PBMap\GeographicCoordinates, @PBMap\PixelCoordinates, PBMap\Zoom)
         PBMap\Dragging = #True
-        ;Mem cursor Coord
+        ; Memorize cursor Coord
         PBMap\MoveStartingPoint\x = CanvasMouseX
         PBMap\MoveStartingPoint\y = CanvasMouseY
         ; Clip MouseX to the map range (in X, the map is infinite)
@@ -2408,7 +2437,11 @@ Module PBMap
         *Tile = EventData() 
         key = *Tile\key
         ; After a Web tile loading thread, clean the tile structure memory and set the image nb in the cache
-        ; avoid to have threads accessing vars (and avoid mutex), see GetImageThread()
+        ; avoid to have threads accessing vars (and avoid some mutex), see GetImageThread()
+        *Tile\Download = 0
+        LockMutex(PBMap\DownloadSlotsMutex)
+        PBMap\DownloadSlots - 1
+        UnlockMutex(PBMap\DownloadSlotsMutex)
         Protected timg = PBMap\MemCache\Images(key)\Tile\nImage ; Get this new tile image nb
         PBMap\MemCache\Images(key)\nImage = timg                ; Stores it in the cache using the key
         FreeMemory(PBMap\MemCache\Images(key)\Tile)             ; Frees the data needed for the thread
@@ -2421,7 +2454,7 @@ Module PBMap
   ; Redraws at regular intervals
   Procedure TimerEvents()
     If EventTimer() = PBMap\Timer And (PBMap\Redraw Or PBMap\Dirty)
-      MemoryCacheManagement()
+      ; MemoryCacheManagement()
       Drawing()
     EndIf    
   EndProcedure 
@@ -2484,6 +2517,11 @@ Module PBMap
     PBMap\Window = Window
     PBMap\Timer = 1
     PBMap\Mode = #MODE_DEFAULT
+    PBMap\DownloadSlotsMutex = CreateMutex()
+    If PBMap\DownloadSlotsMutex = #False
+      MyDebug("Cannot create a mutex", 0)
+      End
+    EndIf
     LoadOptions()
     TechnicalImagesCreation()
     SetLocation(0, 0)
@@ -2799,8 +2837,8 @@ CompilerIf #PB_Compiler_IsMainFile
 CompilerEndIf
 
 ; IDE Options = PureBasic 5.60 (Windows - x64)
-; CursorPosition = 893
-; FirstLine = 894
+; CursorPosition = 1162
+; FirstLine = 1143
 ; Folding = -------------------
 ; EnableThread
 ; EnableXP