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675.1.7
by Olaf 'Rhialto' Seibert
Move the window ring functions to their own file. |
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/*
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* Functions related to the window ring.
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675.1.10
by Olaf 'Rhialto' Seibert
Document some window ring invariants. |
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*
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* Invariants:
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* - If a window is not on the ring, its TwmWindow::ring.next and .prev
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* are both NULL.
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* - If a window is on the ring, they are both not NULL and point to a
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* window which is also on the ring.
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* - Corollary: if a window is the only one on the ring, .next and .prev
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* point to itself.
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* - Functions which act on the "current" ring window, i.e. the window
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* that has most recently been entered and is on the ring, use
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* Scr->RingLeader.
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* - If RingLeader is NULL, fall back to Scr->Ring.
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* - If Ring is NULL, the ring is empty (and RingLeader is also NULL).
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675.1.7
by Olaf 'Rhialto' Seibert
Move the window ring functions to their own file. |
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*/
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#include "ctwm.h" |
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675.1.10
by Olaf 'Rhialto' Seibert
Document some window ring invariants. |
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#include <assert.h> |
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675.1.7
by Olaf 'Rhialto' Seibert
Move the window ring functions to their own file. |
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#include "screen.h" |
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#include "win_ring.h" |
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void
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UnlinkWindowFromRing(TwmWindow *win) |
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{
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TwmWindow *prev = win->ring.prev; |
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TwmWindow *next = win->ring.next; |
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682
by Matthew Fuller
Escape early from UnlinkWindowFromRing() if the window isn't on the |
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// We call this unconditionally at various window deletion times, and
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// if it's not on the ring, there's nothing to do. e.g., if we don't
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// have any WindowRing config enabled...
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if(!WindowIsOnRing(win)) { |
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return; |
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}
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// But if it is, prev/next should always exist.
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675.1.10
by Olaf 'Rhialto' Seibert
Document some window ring invariants. |
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assert(prev != NULL); |
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assert(next != NULL); |
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682
by Matthew Fuller
Escape early from UnlinkWindowFromRing() if the window isn't on the |
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675.1.7
by Olaf 'Rhialto' Seibert
Move the window ring functions to their own file. |
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/*
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* 1. Unlink window
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* 2. If window was only thing in ring, null out ring
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* 3. If window was ring leader, set to next (or null)
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*
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* If the window is the only one in the ring, prev == next == win,
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* so the unlinking effectively is a NOP, but that doesn't matter.
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*/
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prev->ring.next = next; |
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next->ring.prev = prev; |
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win->ring.next = win->ring.prev = NULL; |
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if(Scr->Ring == win) { |
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Scr->Ring = (next != win ? next : NULL); |
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}
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if(!Scr->Ring || Scr->RingLeader == win) { |
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Scr->RingLeader = Scr->Ring; |
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}
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}
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static void |
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AddWindowToRingUnchecked(TwmWindow *win, TwmWindow *after) |
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{
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TwmWindow *before = after->ring.next; |
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win->ring.next = before; |
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win->ring.prev = after; |
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after->ring.next = win; |
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before->ring.prev = win; |
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}
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void
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AddWindowToRing(TwmWindow *win) |
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{
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675.1.10
by Olaf 'Rhialto' Seibert
Document some window ring invariants. |
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assert(win->ring.next == NULL); |
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assert(win->ring.prev == NULL); |
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675.1.7
by Olaf 'Rhialto' Seibert
Move the window ring functions to their own file. |
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if(Scr->Ring) { |
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AddWindowToRingUnchecked(win, Scr->Ring); |
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}
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else { |
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win->ring.next = win->ring.prev = Scr->Ring = win; |
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}
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}
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