libgo/runtime/chan.h

   1 // Copyright 2009 The Go Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style
   3 // license that can be found in the LICENSE file.
   4
   5 typedef struct  WaitQ   WaitQ;
   6 typedef struct  SudoG   SudoG;
   7 typedef struct  Select  Select;
   8 typedef struct  Scase   Scase;
   9
  10 typedef struct  __go_type_descriptor    Type;
  11 typedef struct  __go_channel_type       ChanType;
  12
  13 struct  SudoG
  14 {
  15         G*      g;
  16         uint32* selectdone;
  17         SudoG*  link;
  18         int64   releasetime;
  19         byte*   elem;           // data element
  20         uint32  ticket;
  21 };
  22
  23 struct  WaitQ
  24 {
  25         SudoG*  first;
  26         SudoG*  last;
  27 };
  28
  29 // The garbage collector is assuming that Hchan can only contain pointers into the stack
  30 // and cannot contain pointers into the heap.
  31 struct  Hchan
  32 {
  33         uintgo  qcount;                 // total data in the q
  34         uintgo  dataqsiz;               // size of the circular q
  35         uint16  elemsize;
  36         uint16  pad;                    // ensures proper alignment of the buffer that follows Hchan in memory
  37         bool    closed;
  38         const Type* elemtype;           // element type
  39         uintgo  sendx;                  // send index
  40         uintgo  recvx;                  // receive index
  41         WaitQ   recvq;                  // list of recv waiters
  42         WaitQ   sendq;                  // list of send waiters
  43         Lock;
  44 };
  45
  46 // Buffer follows Hchan immediately in memory.
  47 // chanbuf(c, i) is pointer to the i'th slot in the buffer.
  48 #define chanbuf(c, i) ((byte*)((c)+1)+(uintptr)(c)->elemsize*(i))
  49
  50 enum
  51 {
  52         debug = 0,
  53
  54         // Scase.kind
  55         CaseRecv,
  56         CaseSend,
  57         CaseDefault,
  58 };
  59
  60 struct  Scase
  61 {
  62         SudoG   sg;                     // must be first member (cast to Scase)
  63         Hchan*  chan;                   // chan
  64         uint16  kind;
  65         uint16  index;                  // index to return
  66         bool*   receivedp;              // pointer to received bool (recv2)
  67 };
  68
  69 struct  Select
  70 {
  71         uint16  tcase;                  // total count of scase[]
  72         uint16  ncase;                  // currently filled scase[]
  73         uint16* pollorder;              // case poll order
  74         Hchan** lockorder;              // channel lock order
  75         Scase   scase[1];               // one per case (in order of appearance)
  76 };