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Protocol changes to support server-side delayed echoing

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This commit is contained in:
Keith Winstein
2012-02-03 16:30:33 -05:00
parent da66244eab
commit 5f31fd3f7a
10 changed files with 127 additions and 92 deletions
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terminaloverlay.cpp
+53 -60
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@@ -8,10 +8,10 @@
using namespace Overlay;
bool ConditionalOverlay::start_clock( uint64_t local_frame_acked, uint64_t now )
bool ConditionalOverlay::start_clock( uint64_t local_frame_acked, uint64_t now, unsigned int send_interval )
{
if ( (local_frame_acked >= expiration_frame) && (expiration_time == uint64_t(-1)) ) {
expiration_time = now + 50;
expiration_time = now + 25 + 125 * send_interval / 100;
return true;
}
return false;
@@ -53,7 +53,9 @@ void ConditionalOverlayCell::apply( Framebuffer &fb, uint64_t confirmed_epoch, i
}
}
Validity ConditionalOverlayCell::get_validity( const Framebuffer &fb, int row, uint64_t current_frame, uint64_t now ) const
Validity ConditionalOverlayCell::get_validity( const Framebuffer &fb, int row,
uint64_t sent_frame, uint64_t early_ack, uint64_t late_ack,
uint64_t now ) const
{
if ( !active ) {
return Inactive;
@@ -67,7 +69,7 @@ Validity ConditionalOverlayCell::get_validity( const Framebuffer &fb, int row, u
const Cell &current = *( fb.get_cell( row, col ) );
/* see if it hasn't been updated yet */
if ( current_frame < expiration_frame ) {
if ( early_ack < expiration_frame ) {
return Pending;
}
@@ -92,14 +94,15 @@ Validity ConditionalOverlayCell::get_validity( const Framebuffer &fb, int row, u
assert( expiration_time != uint64_t(-1) );
if ( now < expiration_time ) {
return Pending;
if ( (late_ack >= expiration_frame)
|| ( (sent_frame <= early_ack) && (expiration_time >= now) ) ) {
return IncorrectOrExpired;
}
return IncorrectOrExpired;
return Pending;
}
Validity ConditionalCursorMove::get_validity( const Framebuffer &fb, uint64_t current_frame, uint64_t now ) const
Validity ConditionalCursorMove::get_validity( const Framebuffer &fb, uint64_t sent_frame, uint64_t early_ack, uint64_t late_ack, uint64_t now ) const
{
if ( !active ) {
return Inactive;
@@ -112,7 +115,7 @@ Validity ConditionalCursorMove::get_validity( const Framebuffer &fb, uint64_t cu
return IncorrectOrExpired;
}
if ( current_frame < expiration_frame ) {
if ( early_ack < expiration_frame ) {
return Pending;
}
@@ -123,15 +126,12 @@ Validity ConditionalCursorMove::get_validity( const Framebuffer &fb, uint64_t cu
assert( expiration_time != uint64_t(-1) );
if ( now < expiration_time ) {
return Pending;
if ( (late_ack >= expiration_frame)
|| ( (sent_frame <= early_ack) && (expiration_time >= now) ) ) {
return IncorrectOrExpired;
}
/*
fprintf( stderr, "Bad cursor in %d (I thought (%d,%d) vs actual (%d,%d)).\n", (int)current_frame,
row, col, fb.ds.get_cursor_row(), fb.ds.get_cursor_col() );
*/
return IncorrectOrExpired;
return Pending;
}
void ConditionalCursorMove::apply( Framebuffer &fb, uint64_t confirmed_epoch ) const
@@ -349,6 +349,14 @@ void PredictionEngine::init_cursor( const Framebuffer &fb )
fb.ds.get_cursor_row(),
fb.ds.get_cursor_col(),
prediction_epoch ) );
cursor().active = true;
} else if ( cursor().tentative_until_epoch != prediction_epoch ) {
cursors.push_back( ConditionalCursorMove( local_frame_sent + 1,
cursor().row,
cursor().col,
prediction_epoch ) );
cursor().active = true;
}
}
@@ -369,22 +377,13 @@ void PredictionEngine::cull( const Framebuffer &fb )
continue;
}
/* smash through "shell prompt" barrier if host has let us */
if ( fb.ds.get_cursor_row() == i->row_num ) {
if ( i->first_col != INT_MAX ) {
if ( fb.ds.get_cursor_col() < i->first_col ) {
i->first_col = 0;
}
} else {
i->first_col = fb.ds.get_cursor_col();
}
}
for ( auto j = i->overlay_cells.begin(); j != i->overlay_cells.end(); j++ ) {
if ( j->start_clock( local_frame_acked, now ) ) {
if ( j->start_clock( local_frame_acked, now, send_interval ) ) {
last_scheduled_timeout = max( last_scheduled_timeout, j->expiration_time );
}
switch ( j->get_validity( fb, i->row_num, local_frame_acked, now ) ) {
switch ( j->get_validity( fb, i->row_num,
local_frame_sent, local_frame_acked, local_frame_late_acked,
now ) ) {
case IncorrectOrExpired:
if ( j->tentative( confirmed_epoch ) ) {
@@ -440,29 +439,23 @@ void PredictionEngine::cull( const Framebuffer &fb )
if ( j->display_time != uint64_t(-1) ) {
if ( now - j->display_time < 75 ) {
if ( flagging > 0 ) {
flagging--;
if ( flag_score > -10 ) {
flag_score--;
}
}
}
/* no break */
case CorrectNoCredit:
if ( i->first_col != INT_MAX ) {
if ( j->col < i->first_col ) {
i->first_col = 0;
}
} else {
i->first_col = j->col;
}
j->reset();
break;
case Pending:
if ( j->display_time != uint64_t(-1) ) {
if ( now - j->display_time >= 150 ) {
flagging = 10;
if ( now - j->display_time > 150 ) {
if ( flag_score < 10 ) {
flag_score++;
}
}
}
break;
@@ -474,15 +467,24 @@ void PredictionEngine::cull( const Framebuffer &fb )
i = inext;
}
/* control flagging with hysteresis */
if ( flag_score > 5 ) {
flagging = true;
} else if ( flag_score < -5 ) {
flagging = false;
}
/* go through cursor predictions */
for ( auto it = cursors.begin(); it != cursors.end(); it++ ) {
if ( it->start_clock( local_frame_acked, now ) ) {
if ( it->start_clock( local_frame_acked, now, send_interval ) ) {
last_scheduled_timeout = max( last_scheduled_timeout, it->expiration_time );
}
}
if ( !cursors.empty() ) {
if ( cursor().get_validity( fb, local_frame_acked, now ) == IncorrectOrExpired ) {
if ( cursor().get_validity( fb,
local_frame_sent, local_frame_acked, local_frame_late_acked,
now ) == IncorrectOrExpired ) {
/*
fprintf( stderr, "Sadly, we're predicting (%d,%d) vs. (%d,%d) [tau: %ld, expiration_time=%ld, now=%ld]\n",
cursor().row, cursor().col,
@@ -497,7 +499,10 @@ void PredictionEngine::cull( const Framebuffer &fb )
}
}
cursors.remove_if( [&]( ConditionalCursorMove &x ) { return (x.get_validity( fb, local_frame_acked, now ) != Pending); } );
cursors.remove_if( [&]( const ConditionalCursorMove &x ) {
return (x.get_validity( fb,
local_frame_sent, local_frame_acked, local_frame_late_acked,
now ) != Pending); } );
}
ConditionalOverlayRow & PredictionEngine::get_or_make_row( int row_num, int num_cols )
@@ -554,9 +559,6 @@ void PredictionEngine::new_user_byte( char the_byte, const Framebuffer &fb )
if ( ch == 0x7f ) { /* backspace */
// fprintf( stderr, "Backspace.\n" );
ConditionalOverlayRow &the_row = get_or_make_row( cursor().row, fb.ds.get_width() );
if ( cursor().col <= the_row.first_col ) {
become_tentative();
}
if ( cursor().col > 0 ) {
cursor().col--;
@@ -654,10 +656,12 @@ void PredictionEngine::new_user_byte( char the_byte, const Framebuffer &fb )
*/
cursor().expire( local_frame_sent + 1 );
cursor().col++;
/* do we need to wrap? */
if ( cursor().col >= fb.ds.get_width() ) {
if ( cursor().col < fb.ds.get_width() - 1 ) {
cursor().col++;
} else {
become_tentative();
newline_carriage_return( fb );
}
}
@@ -681,10 +685,6 @@ void PredictionEngine::new_user_byte( char the_byte, const Framebuffer &fb )
}
} else if ( act->char_present && (act->ch == L'D') ) { /* left arrow */
init_cursor( fb );
ConditionalOverlayRow &the_row = get_or_make_row( cursor().row, fb.ds.get_width() );
if ( cursor().col <= the_row.first_col ) {
become_tentative();
}
if ( cursor().col > 0 ) {
cursor().col--;
@@ -733,13 +733,6 @@ void PredictionEngine::become_tentative( void )
{
prediction_epoch++;
if ( !cursors.empty() ) {
cursors.push_back( ConditionalCursorMove( local_frame_sent + 1,
cursor().row,
cursor().col,
prediction_epoch ) );
cursor().active = true;
}
/*
fprintf( stderr, "Now tentative in epoch %lu (confirmed=%lu)\n",
prediction_epoch, confirmed_epoch );