76   static Segment SentinelSegment;  variable
83     Segment *S = &SentinelSegment;
107       DCHECK_NE(S, &SentinelSegment);
108       DCHECK_NE(S->Next, &SentinelSegment);
110       DCHECK_NE(S, &SentinelSegment);
115       DCHECK_NE(S, &SentinelSegment);
120         DCHECK_NE(S->Prev, &SentinelSegment);
152       DCHECK_NE(S, &SentinelSegment);
210     if (Freelist != &SentinelSegment) {  in NewSegment()
223       DCHECK_EQ(Freelist->Prev, &SentinelSegment);  in NewSegment()
241       if (Freelist != &SentinelSegment)  in NewSegment()
242         Freelist->Prev = &SentinelSegment;  in NewSegment()
244       FreeSegment->Next = &SentinelSegment;  in NewSegment()
245       FreeSegment->Prev = &SentinelSegment;  in NewSegment()
248       DCHECK_EQ(Freelist->Prev, &SentinelSegment);  in NewSegment()
249       DCHECK_NE(FreeSegment, &SentinelSegment);  in NewSegment()
258     new (SegmentBlock.Data) Segment{&SentinelSegment, &SentinelSegment, {0}};  in NewSegment()
264     DCHECK_EQ(Head, &SentinelSegment);  in InitHeadAndTail()
265     DCHECK_EQ(Tail, &SentinelSegment);  in InitHeadAndTail()
269     DCHECK_EQ(S->Next, &SentinelSegment);  in InitHeadAndTail()
270     DCHECK_EQ(S->Prev, &SentinelSegment);  in InitHeadAndTail()
271     DCHECK_NE(S, &SentinelSegment);  in InitHeadAndTail()
275     DCHECK_EQ(Tail->Next, &SentinelSegment);  in InitHeadAndTail()
276     DCHECK_EQ(Tail->Prev, &SentinelSegment);  in InitHeadAndTail()
284     DCHECK_NE(Tail, &SentinelSegment);  in AppendNewSegment()
285     DCHECK_EQ(Tail->Next, &SentinelSegment);  in AppendNewSegment()
286     DCHECK_EQ(S->Prev, &SentinelSegment);  in AppendNewSegment()
287     DCHECK_EQ(S->Next, &SentinelSegment);  in AppendNewSegment()
292     DCHECK_EQ(Tail->Next, &SentinelSegment);  in AppendNewSegment()
299         Head(&SentinelSegment),  in Array()
300         Tail(&SentinelSegment),  in Array()
301         Freelist(&SentinelSegment),  in Array()
305                                   Head(&SentinelSegment),  in Array()
306                                   Tail(&SentinelSegment),  in Array()
307                                   Freelist(&SentinelSegment),  in Array()
319     O.Head = &SentinelSegment;  in Array()
320     O.Tail = &SentinelSegment;  in Array()
322     O.Freelist = &SentinelSegment;  in Array()
329     O.Head = &SentinelSegment;
331     O.Tail = &SentinelSegment;
333     O.Freelist = &SentinelSegment;
355     DCHECK((Size == 0 && Head == &SentinelSegment && Head == Tail) ||  in AppendEmplace()
356            (Size != 0 && Head != &SentinelSegment && Tail != &SentinelSegment));  in AppendEmplace()
357     if (UNLIKELY(Head == &SentinelSegment)) {  in AppendEmplace()
363     DCHECK_NE(Head, &SentinelSegment);  in AppendEmplace()
364     DCHECK_NE(Tail, &SentinelSegment);  in AppendEmplace()
371     DCHECK_NE(Tail, &SentinelSegment);  in AppendEmplace()
387     DCHECK((Size == 0 && Head == &SentinelSegment && Head == Tail) ||  in Append()
388            (Size != 0 && Head != &SentinelSegment && Tail != &SentinelSegment));  in Append()
389     if (UNLIKELY(Head == &SentinelSegment)) {  in Append()
395     DCHECK_NE(Head, &SentinelSegment);  in Append()
396     DCHECK_NE(Tail, &SentinelSegment);  in Append()
403     DCHECK_NE(Tail, &SentinelSegment);  in Append()
422       DCHECK_NE(S, &SentinelSegment);
431     DCHECK_NE(Head, &SentinelSegment);  in front()
437     DCHECK_NE(Tail, &SentinelSegment);  in back()
516       DCHECK_NE(Head, &SentinelSegment);  in trim()
517       DCHECK_NE(Tail, &SentinelSegment);  in trim()
518       DCHECK_EQ(Tail->Next, &SentinelSegment);  in trim()
520       if (Freelist == &SentinelSegment) {  in trim()
558         SPT->Next = &SentinelSegment;  in trim()
559         Tail->Prev = &SentinelSegment;  in trim()
565         DCHECK_EQ(Tail->Next, &SentinelSegment);  in trim()
566         DCHECK_EQ(Freelist->Prev, &SentinelSegment);  in trim()
601         ST->Prev = &SentinelSegment;  in trim()
602         SPT->Next = &SentinelSegment;  in trim()
607         DCHECK_EQ(Tail->Next, &SentinelSegment);  in trim()
608         DCHECK_EQ(Freelist->Prev, &SentinelSegment);  in trim()
616     if (Tail == &SentinelSegment)  in trim()
620         (Size == 0 && Head == &SentinelSegment && Tail == &SentinelSegment) ||  in trim()
621         (Size != 0 && Head != &SentinelSegment && Tail != &SentinelSegment));  in trim()
623         (Freelist != &SentinelSegment && Freelist->Prev == &SentinelSegment) ||  in trim()
624         (Freelist == &SentinelSegment && Tail->Next == &SentinelSegment));  in trim()
646 typename Array<T>::Segment Array<T>::SentinelSegment{
647     &Array<T>::SentinelSegment, &Array<T>::SentinelSegment, {'\0'}};