minor correction

[lttv.git] / ltt / branches / poly / doc / developer / lttvwindow_events_delivery.txt

diff --git a/ltt/branches/poly/doc/developer/lttvwindow_events_delivery.txt b/ltt/branches/poly/doc/developer/lttvwindow_events_delivery.txt
index bbcd8bf37078fd3533c345d0f3442cafadb5d1cd..c7fe77d05298b3ee87f55ed0842027cdb4594118 100644 (file)
--- a/ltt/branches/poly/doc/developer/lttvwindow_events_delivery.txt
+++ b/ltt/branches/poly/doc/developer/lttvwindow_events_delivery.txt
@@ -141,8 +141,12 @@ Added to the lttvwindow API :
 
 
 void lttvwindow_events_request
 
 
 void lttvwindow_events_request

-( MainWindow                  *main_win,
-  EventsRequest               *events_request);
+( Tab                  *tab,
+  const EventsRequest  *events_request);
+
+void lttvwindow_events_request_remove_all
+( Tab                *tab,
+  gconstpointer       viewer);

 
 
 Internal functions :
 
 
 Internal functions :


@@ -150,165 +154,106 @@ Internal functions :
 - lttvwindow_process_pending_requests
 
 
 - lttvwindow_process_pending_requests
 
 

+Events Requests Removal

 
 

-Implementation
+A new API function will be necessary to let viewers remove all event requests
+they have made previously. By allowing this, no more out of bound requests will
+be serviced : a viewer that sees its time interval changed before the first
+servicing is completed can clear its previous events requests and make a new
+one for the new interval needed, considering the finished chunks as completed
+area.

 
 

+It is also very useful for dealing with the viewer destruction case : the viewer
+just has to remove its events requests from the main window before it gets
+destroyed.

 
 

-- Type LttvHooks

 
 

-see hook_prio.txt
+Permitted GTK Events Between Chunks

 
 

-The viewers will just have to pass hooks to the main window through this type,
-using the hook.h interface to manipulate it. Then, the main window will add
-them and remove them from the context to deliver exactly the events requested by
-each viewer through process traceset.
+All GTK Events will be enabled between chunks. This is due to the fact that the
+background processing and a high priority request are seen as the same case.
+While a background processing is in progress, the whole graphical interface must
+be enabled.

 
 

+We needed to deal with the coherence of background processing and diverse GTK
+events anyway. This algorithm provides a generalized way to deal with any type
+of request and any GTK events.

 
 

-- lttvwindow_events_request

 
 

-It adds the an EventsRequest struct to the array of time requests
-pending and registers a pending request for the next g_idle if none is
-registered. The viewer can access this structure during the read as its
-hook_data. Only the stop_flag can be changed by the viewer through the
-event hooks.
+Background Computation Request

 
 

-typedef struct _EventsRequest {
-  gpointer                    viewer_data;
-  LttTime                     start_time,       /* Unset : { 0, 0 }         */
-  LttvTracesetContextPosition start_position,   /* Unset : num_traces = 0   */
-  gboolean                    stop_flag,        /* Continue:TRUE Stop:FALSE */
-  LttTime                     end_time,         /* Unset : { 0, 0 }         */
-  guint                       num_events,       /* Unset : G_MAXUINT        */
-  LttvTracesetContextPosition end_position,     /* Unset : num_traces = 0   */
-  LttvHooks                  *before_traceset,  /* Unset : NULL             */
-  LttvHooks                  *before_trace,     /* Unset : NULL             */
-  LttvHooks                  *before_tracefile, /* Unset : NULL             */
-  LttvHooks                  *event,            /* Unset : NULL             */
-  LttvHooksById              *event_by_id,      /* Unset : NULL             */
-  LttvHooks                  *after_tracefile,  /* Unset : NULL             */
-  LttvHooks                  *after_trace,      /* Unset : NULL             */
-  LttvHooks                  *after_traceset    /* Unset : NULL             */
-} EventsRequest;
+The types of background computation that can be requested by a viewer : state
+computation (main window scope) or viewer specific background computation.

 
 

+A background computation request is asked via lttvwindow_events_request, with a
+priority field set with a low priority.

 
 

-- lttvwindow_process_pending_requests
+In the case of a background computation with viewer pointer field set to NULL,
+if a lttvwindow_events_request_remove_all is done on the viewer pointer, it will
+not affect the state computation as no viewer pointer will have been passed in
+the initial request. This is the expected result. For the background processings
+that call viewer's hooks, they will be removed.

 
 

-This internal function gets called by g_idle, taking care of the pending
-requests. It is responsible for concatenation of time intervals and position
-requests. It does it with the following algorithm organizing process traceset
-calls. Here is the detailed description of the way it works :

 
 

+A New "Redraw" Button

 
 

-- Events Requests Servicing Algorithm
+It will be used to redraw the viewers entirely. It is useful to restart the
+servicing after a "stop" action.

 
 

-Data structures necessary :
+A New "Continue" Button

 
 

-List of requests added to context : list_in
-List of requests not added to context : list_out
+It will tell the viewers to send requests for damaged areas. It is useful to
+complete the servicing after a "stop" action.

 
 

-Initial state :

 
 

-list_in : empty
-list_out : many events requests

 
 

+Tab change

 
 

-While list_in !empty and list_out !empty
-  1. If list_in is empty (need a seek)
-    1.1 Add requests to list_in
-      1.1.1 Find all time requests with the lowest start time in list_out 
-            (ltime)
-      1.1.2 Find all position requests with the lowest position in list_out
-            (lpos)
-      1.1.3 If lpos.start time < ltime
-        - Add lpos to list_in, remove them from list_out
-      1.1.4 Else, (lpos.start time >= ltime)
-        - Add ltime to list_in, remove them from list_out
-    1.2 Seek
-      1.2.1 If first request in list_in is a time request
-        1.2.1.1 Seek to that time
-      1.2.2 Else, the first request in list_in is a position request
-        1.2.2.1 Seek to that position
-    1.3 Call begin for all list_in members
-      (1.3.1 begin hooks called)
-      (1.3.2 middle hooks added)
-  2. Else, list_in is not empty, we continue a read
-    2.1 For each req of list_out
-    - if req.start time == current context time
-      - Add to list_in, remove from list_out
-      - Call begin
-    - if req.start position == current position
-      - Add to list_in, remove from list_out
-      - Call begin
+If a tab change occurs, we still want to do background processing.
+Events requests must be stocked in a list located in the same scope than the
+traceset context. Right now, this is tab scope. All functions called from the
+request servicing function must _not_ use the current_tab concept, as it may
+change. The idle function must the take a tab, and not the main window, as
+parameter.

 
 

-  3. Find end criterions
-    3.1 End time
-      3.1.1 Find lowest end time in list_in
-      3.1.2 Find lowest start time in list_out
-      3.1.3 Use lowest of both as end time
-    3.2 Number of events
-      3.2.1 Find lowest number of events in list_in
-    3.3 End position
-      3.3.1 Find lowest end position in list_in
-      3.3.2 Find lowest start position in list_out
-      3.3.3 Use lowest of both as end position
+If a tab is removed, its associated idle events requests servicing function must
+also be removed.

 
 

-  4. Call process traceset middle
-    4.1 Call process traceset middle (Use end criterion found in 3)
-      * note : end criterion can also be viewer's hook returning TRUE
-  5. After process traceset middle
-    - if current context time > traceset.end time
-      - For each req in list_in
-        - Call end for req
-        - remove req from list_in
-    5.1 For each req in list_in
-          - req.num -= count
-          - if req.num == 0
-            - Call end for req
-            - remove req from list_in
-          - if current context time > req.end time
-            - Call end for req
-            - remove req from list_in
-          - if req.end pos == current pos
-            - Call end for req
-            - remove req from list_in
-          - if req.stop_flag == TRUE
-            - Call end for req
-            - remove req from list_in
+It now looks a lot more useful to give a Tab* to the viewer instead of a
+MainWindow*, as all the information needed by the viewer is located at the tab
+level. It will diminish the dependance upon the current tab concept.

 
 
 
 
 
 

-Notes :
-End criterions for process traceset middle :
-If the criterion is reached, event is out of boundaries and we return.
-Current time >= End time
-Event count > Number of events
-Current position >= End position
-Last hook list called returned TRUE
-
-The >= for position is necessary to make ensure consistency between start time
-requests and positions requests that happens to be at the exact same start time
-and position.
+Idle function (lttvwindow_process_pending_requests)

 
 

+The idle function must return FALSE to be removed from the idle functions when
+no more events requests are pending. Otherwise, it returns TRUE. It will service
+requests until there is no more request left.

 
 
 
 

-Weaknesses
-
-- None (nearly?) :)

 
 
 
 

-Strengths
+Implementation

 
 

-- Removes the need for filtering of information supplied to the viewers.

 
 

-- Viewers have a better control on their data input.
+- Type LttvHooks

 
 

-- Solves all the weaknesses idenfied in the actual boundaryless traceset
-reading.
+see hook_prio.txt

 
 

+The viewers will just have to pass hooks to the main window through this type,
+using the hook.h interface to manipulate it. Then, the main window will add
+them and remove them from the context to deliver exactly the events requested by
+each viewer through process traceset.

 
 
 
 

+- lttvwindow_events_request

 
 

-- Revised Events Requests Servicing Algorithm (v2)
+It adds the an EventsRequest struct to the array of time requests
+pending and registers a pending request for the next g_idle if none is
+registered. The viewer can access this structure during the read as its
+hook_data. Only the stop_flag can be changed by the viewer through the
+event hooks.

 
 typedef LttvEventsRequestPrio guint;
 
 
 typedef LttvEventsRequestPrio guint;
 


@@ -335,6 +280,26 @@ typedef struct _EventsRequest {
 } EventsRequest;
 
 
 } EventsRequest;
 
 

+
+- lttvwindow_events_request_remove_all
+
+It removes all the events requests from the pool that has their "viewer" field
+maching the viewer pointer given in argument.
+
+It calls the traceset/trace/tracefile end hooks for each request removed.
+
+
+- lttvwindow_process_pending_requests
+
+This internal function gets called by g_idle, taking care of the pending
+requests. It is responsible for concatenation of time intervals and position
+requests. It does it with the following algorithm organizing process traceset
+calls. Here is the detailed description of the way it works :
+
+
+
+- Revised Events Requests Servicing Algorithm (v2)
+

 The reads are splitted in chunks. After a chunk is over, we want to check if
 there is a GTK Event pending and execute it. It can add or remove events 
 requests from the event requests list. If it happens, we want to start over
 The reads are splitted in chunks. After a chunk is over, we want to check if
 there is a GTK Event pending and execute it. It can add or remove events 
 requests from the event requests list. If it happens, we want to start over


@@ -487,3 +452,26 @@ low priority will loose its state and will have to seek back. It should not
 occur often. The solution to it would be to save one state per priority.
 
 
 occur often. The solution to it would be to save one state per priority.
 
 

+
+
+
+
+Weaknesses
+
+- There is a possibility that we must use seek if more than one interruption
+  occurs, i.e. low priority interrupted by addition of high priority, and then
+  high priority interrupted. The seek will be necessary for the low priority.
+  It could be a good idea to keep one saved_state per priority ?
+
+
+Strengths
+
+- Removes the need for filtering of information supplied to the viewers.
+
+- Viewers have a better control on their data input.
+
+- Solves all the weaknesses idenfied in the actual boundaryless traceset
+reading.
+
+- Background processing available.
+