src/bin/lttng-relayd/tracefile-array.h

   1 #ifndef _TRACEFILE_ARRAY_H
   2 #define _TRACEFILE_ARRAY_H
   3
   4 /*
   5  * Copyright (C) 2015 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   6  *
   7  * SPDX-License-Identifier: GPL-2.0-only
   8  *
   9  */
  10
  11 #include <limits.h>
  12 #include <inttypes.h>
  13 #include <pthread.h>
  14 #include <stdbool.h>
  15
  16 struct tracefile {
  17         /* Per-tracefile head/tail seq. */
  18         uint64_t seq_head;      /* Newest seqcount. Inclusive. */
  19         uint64_t seq_tail;      /* Oldest seqcount. Inclusive. */
  20 };
  21
  22 enum tracefile_rotate_type {
  23         TRACEFILE_ROTATE_READ,
  24         TRACEFILE_ROTATE_WRITE,
  25 };
  26
  27 /*
  28  * Represents an array of trace files in a stream.
  29  * head is the most recent file/trace packet.
  30  * tail is the oldest file/trace packet.
  31  *
  32  * There are two heads: a "read" head and a "write" head. The "write" head is
  33  * the position of the newest data file. The "read" head position is only moved
  34  * forward when the index is received.
  35  *
  36  * The viewer uses the "read" head position as upper bound, which
  37  * ensures it never attempts to open a non-existing index file.
  38  */
  39 struct tracefile_array {
  40         struct tracefile *tf;
  41         size_t count;
  42
  43         /* Current head/tail files. */
  44         uint64_t file_head_read;
  45         uint64_t file_head_write;
  46         uint64_t file_tail;
  47
  48         /* Overall head/tail seq for the entire array. Inclusive. */
  49         uint64_t seq_head;
  50         uint64_t seq_tail;
  51 };
  52
  53 struct tracefile_array *tracefile_array_create(size_t count);
  54 void tracefile_array_destroy(struct tracefile_array *tfa);
  55
  56 void tracefile_array_file_rotate(struct tracefile_array *tfa, enum tracefile_rotate_type type);
  57 void tracefile_array_commit_seq(struct tracefile_array *tfa,
  58                 uint64_t new_seq_head);
  59 void tracefile_array_reset(struct tracefile_array *tfa);
  60
  61 uint64_t tracefile_array_get_read_file_index_head(struct tracefile_array *tfa);
  62 /* May return -1ULL in the case where we have not received any indexes yet. */
  63 uint64_t tracefile_array_get_seq_head(struct tracefile_array *tfa);
  64
  65 uint64_t tracefile_array_get_file_index_tail(struct tracefile_array *tfa);
  66 /* May return -1ULL in the case where we have not received any indexes yet. */
  67 uint64_t tracefile_array_get_seq_tail(struct tracefile_array *tfa);
  68
  69 bool tracefile_array_seq_in_file(struct tracefile_array *tfa,
  70                 uint64_t file_index, uint64_t seq);
  71
  72 #endif /* _STREAM_H */