plugins/ctf/common/metadata/decoder.h

   1 #ifndef _METADATA_DECODER_H
   2 #define _METADATA_DECODER_H
   3
   4 /*
   5  * Copyright 2016-2017 - Philippe Proulx <pproulx@efficios.com>
   6  *
   7  * Permission is hereby granted, free of charge, to any person obtaining a copy
   8  * of this software and associated documentation files (the "Software"), to deal
   9  * in the Software without restriction, including without limitation the rights
  10  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  11  * copies of the Software, and to permit persons to whom the Software is
  12  * furnished to do so, subject to the following conditions:
  13  *
  14  * The above copyright notice and this permission notice shall be included in
  15  * all copies or substantial portions of the Software.
  16  */
  17
  18 #include <stdint.h>
  19 #include <stdbool.h>
  20
  21 #include <babeltrace/babeltrace.h>
  22
  23 /* A CTF metadata decoder object */
  24 struct ctf_metadata_decoder;
  25
  26 /* CTF metadata decoder status */
  27 enum ctf_metadata_decoder_status {
  28         CTF_METADATA_DECODER_STATUS_OK                  = 0,
  29         CTF_METADATA_DECODER_STATUS_ERROR               = -1,
  30         CTF_METADATA_DECODER_STATUS_INCOMPLETE          = -2,
  31         CTF_METADATA_DECODER_STATUS_INVAL_VERSION       = -3,
  32         CTF_METADATA_DECODER_STATUS_IR_VISITOR_ERROR    = -4,
  33 };
  34
  35 /* Decoding configuration */
  36 struct ctf_metadata_decoder_config {
  37         int64_t clock_class_offset_s;
  38         int64_t clock_class_offset_ns;
  39 };
  40
  41 /*
  42  * Creates a CTF metadata decoder.
  43  *
  44  * Returns `NULL` on error.
  45  */
  46 BT_HIDDEN
  47 struct ctf_metadata_decoder *ctf_metadata_decoder_create(
  48                 const struct ctf_metadata_decoder_config *config);
  49
  50 /*
  51  * Destroys a CTF metadata decoder that you created with
  52  * ctf_metadata_decoder_create().
  53  */
  54 BT_HIDDEN
  55 void ctf_metadata_decoder_destroy(
  56                 struct ctf_metadata_decoder *metadata_decoder);
  57
  58 /*
  59  * Decodes a new chunk of CTF metadata.
  60  *
  61  * This function reads the metadata from the current position of `fp`
  62  * until the end of this file stream. If it finds new information (new
  63  * event class, new stream class, or new clock class), it appends this
  64  * information to the decoder's trace object (as returned by
  65  * ctf_metadata_decoder_get_ir_trace_class()), or it creates this trace.
  66  *
  67  * The metadata can be packetized or not.
  68  *
  69  * The metadata chunk needs to be complete and scannable, that is,
  70  * zero or more complete top-level blocks. If it's incomplete, this
  71  * function returns `CTF_METADATA_DECODER_STATUS_INCOMPLETE`. If this
  72  * function returns `CTF_METADATA_DECODER_STATUS_INCOMPLETE`, then you
  73  * need to call it again with the same metadata and more to make it
  74  * complete. For example:
  75  *
  76  *     First call:  event { name = hell
  77  *     Second call: event { name = hello_world; ... };
  78  *
  79  * If the conversion from the metadata text to CTF IR objects fails,
  80  * this function returns `CTF_METADATA_DECODER_STATUS_IR_VISITOR_ERROR`.
  81  *
  82  * If everything goes as expected, this function returns
  83  * `CTF_METADATA_DECODER_STATUS_OK`.
  84  */
  85 BT_HIDDEN
  86 enum ctf_metadata_decoder_status ctf_metadata_decoder_decode(
  87                 struct ctf_metadata_decoder *metadata_decoder, FILE *fp);
  88
  89 BT_HIDDEN
  90 bt_trace_class *ctf_metadata_decoder_get_ir_trace_class(
  91                 struct ctf_metadata_decoder *mdec);
  92
  93 BT_HIDDEN
  94 struct ctf_trace_class *ctf_metadata_decoder_borrow_ctf_trace_class(
  95                 struct ctf_metadata_decoder *mdec);
  96
  97 /*
  98  * Checks whether or not a given metadata file stream is packetized, and
  99  * if so, sets `*byte_order` to the byte order of the first packet.
 100  */
 101 BT_HIDDEN
 102 bool ctf_metadata_decoder_is_packetized(FILE *fp, int *byte_order);
 103
 104 /*
 105  * Decodes a packetized metadata file stream to a NULL-terminated
 106  * text buffer using the given byte order.
 107  */
 108 BT_HIDDEN
 109 int ctf_metadata_decoder_packetized_file_stream_to_buf(
 110                 FILE *fp, char **buf, int byte_order);
 111
 112 #endif /* _METADATA_DECODER_H */