--- /dev/null
+#ifndef CTF_MSG_ITER_H
+#define CTF_MSG_ITER_H
+
+/*
+ * Babeltrace - CTF message iterator
+ * ¯¯¯¯¯ ¯¯¯¯
+ * Copyright (c) 2015-2016 EfficiOS Inc. and Linux Foundation
+ * Copyright (c) 2015-2016 Philippe Proulx <pproulx@efficios.com>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#include <stdint.h>
+#include <stdio.h>
+#include <stddef.h>
+#include <babeltrace/babeltrace.h>
+#include <babeltrace/babeltrace-internal.h>
+
+#include "../metadata/ctf-meta.h"
+
+/**
+ * @file ctf-msg-iter.h
+ *
+ * CTF message iterator
+ * ¯¯¯¯¯ ¯¯¯¯
+ * This is a common internal API used by CTF source plugins. It allows
+ * one to get messages from a user-provided medium.
+ */
+
+/**
+ * Medium operations status codes.
+ */
+enum bt_msg_iter_medium_status {
+ /**
+ * End of file.
+ *
+ * The medium function called by the message iterator
+ * function reached the end of the file.
+ */
+ BT_MSG_ITER_MEDIUM_STATUS_EOF = 1,
+
+ /**
+ * There is no data available right now, try again later.
+ */
+ BT_MSG_ITER_MEDIUM_STATUS_AGAIN = 11,
+
+ /** Unsupported operation. */
+ BT_MSG_ITER_MEDIUM_STATUS_UNSUPPORTED = -3,
+
+ /** Invalid argument. */
+ BT_MSG_ITER_MEDIUM_STATUS_INVAL = -2,
+
+ /** General error. */
+ BT_MSG_ITER_MEDIUM_STATUS_ERROR = -1,
+
+ /** Everything okay. */
+ BT_MSG_ITER_MEDIUM_STATUS_OK = 0,
+};
+
+/**
+ * CTF message iterator API status code.
+ */
+enum bt_msg_iter_status {
+ /**
+ * End of file.
+ *
+ * The medium function called by the message iterator
+ * function reached the end of the file.
+ */
+ BT_MSG_ITER_STATUS_EOF = BT_MSG_ITER_MEDIUM_STATUS_EOF,
+
+ /**
+ * There is no data available right now, try again later.
+ *
+ * Some condition resulted in the
+ * bt_msg_iter_medium_ops::request_bytes() user function not
+ * having access to any data now. You should retry calling the
+ * last called message iterator function once the situation
+ * is resolved.
+ */
+ BT_MSG_ITER_STATUS_AGAIN = BT_MSG_ITER_MEDIUM_STATUS_AGAIN,
+
+ /** Invalid argument. */
+ BT_MSG_ITER_STATUS_INVAL = BT_MSG_ITER_MEDIUM_STATUS_INVAL,
+
+ /** Unsupported operation. */
+ BT_MSG_ITER_STATUS_UNSUPPORTED = BT_MSG_ITER_MEDIUM_STATUS_UNSUPPORTED,
+
+ /** General error. */
+ BT_MSG_ITER_STATUS_ERROR = BT_MSG_ITER_MEDIUM_STATUS_ERROR,
+
+ /** Everything okay. */
+ BT_MSG_ITER_STATUS_OK = 0,
+};
+
+/**
+ * CTF message iterator seek operation directives.
+ */
+enum bt_msg_iter_seek_whence {
+ /**
+ * Set the iterator's position to an absolute offset in the underlying
+ * medium.
+ */
+ BT_MSG_ITER_SEEK_WHENCE_SET,
+};
+
+/**
+ * Medium operations.
+ *
+ * Those user functions are called by the message iterator
+ * functions to request medium actions.
+ */
+struct bt_msg_iter_medium_ops {
+ /**
+ * Returns the next byte buffer to be used by the binary file
+ * reader to deserialize binary data.
+ *
+ * This function \em must be defined.
+ *
+ * The purpose of this function is to return a buffer of bytes
+ * to the message iterator, of a maximum of \p request_sz
+ * bytes. If this function cannot return a buffer of at least
+ * \p request_sz bytes, it may return a smaller buffer. In
+ * either cases, \p buffer_sz must be set to the returned buffer
+ * size (in bytes).
+ *
+ * The returned buffer's ownership remains the medium, in that
+ * it won't be freed by the message iterator functions. The
+ * returned buffer won't be modified by the message
+ * iterator functions either.
+ *
+ * When this function is called for the first time for a given
+ * file, the offset within the file is considered to be 0. The
+ * next times this function is called, the returned buffer's
+ * byte offset within the complete file must be the previous
+ * offset plus the last returned value of \p buffer_sz by this
+ * medium.
+ *
+ * This function must return one of the following statuses:
+ *
+ * - <b>#BT_MSG_ITER_MEDIUM_STATUS_OK</b>: Everything
+ * is okay, i.e. \p buffer_sz is set to a positive value
+ * reflecting the number of available bytes in the buffer
+ * starting at the address written in \p buffer_addr.
+ * - <b>#BT_MSG_ITER_MEDIUM_STATUS_AGAIN</b>: No data is
+ * available right now. In this case, the message
+ * iterator function called by the user returns
+ * #BT_MSG_ITER_STATUS_AGAIN, and it is the user's
+ * responsibility to make sure enough data becomes available
+ * before calling the \em same message iterator
+ * function again to continue the decoding process.
+ * - <b>#BT_MSG_ITER_MEDIUM_STATUS_EOF</b>: The end of
+ * the file was reached, and no more data will ever be
+ * available for this file. In this case, the message
+ * iterator function called by the user returns
+ * #BT_MSG_ITER_STATUS_EOF. This must \em not be
+ * returned when returning at least one byte of data to the
+ * caller, i.e. this must be returned when there's
+ * absolutely nothing left; should the request size be
+ * larger than what's left in the file, this function must
+ * return what's left, setting \p buffer_sz to the number of
+ * remaining bytes, and return
+ * #BT_MSG_ITER_MEDIUM_STATUS_EOF on the \em following
+ * call.
+ * - <b>#BT_MSG_ITER_MEDIUM_STATUS_ERROR</b>: A fatal
+ * error occured during this operation. In this case, the
+ * message iterator function called by the user returns
+ * #BT_MSG_ITER_STATUS_ERROR.
+ *
+ * If #BT_MSG_ITER_MEDIUM_STATUS_OK is not returned, the
+ * values of \p buffer_sz and \p buffer_addr are \em ignored by
+ * the caller.
+ *
+ * @param request_sz Requested buffer size (bytes)
+ * @param buffer_addr Returned buffer address
+ * @param buffer_sz Returned buffer's size (bytes)
+ * @param data User data
+ * @returns Status code (see description above)
+ */
+ enum bt_msg_iter_medium_status (* request_bytes)(
+ size_t request_sz, uint8_t **buffer_addr,
+ size_t *buffer_sz, void *data);
+
+ /**
+ * Repositions the underlying stream's position.
+ *
+ * This *optional* method repositions the underlying stream
+ * to a given absolute or relative position, as indicated by
+ * the whence directive.
+ *
+ * @param whence One of #bt_msg_iter_seek_whence values
+ * @param offset Offset to use for the given directive
+ * @param data User data
+ * @returns One of #bt_msg_iter_medium_status values
+ */
+ enum bt_msg_iter_medium_status (* seek)(
+ enum bt_msg_iter_seek_whence whence,
+ off_t offset, void *data);
+
+ /**
+ * Returns a stream instance (weak reference) for the given
+ * stream class.
+ *
+ * This is called after a packet header is read, and the
+ * corresponding stream class is found by the message
+ * iterator.
+ *
+ * @param stream_class Stream class of the stream to get
+ * @param stream_id Stream (instance) ID of the stream
+ * to get (-1ULL if not available)
+ * @param data User data
+ * @returns Stream instance (weak reference) or
+ * \c NULL on error
+ */
+ bt_stream * (* borrow_stream)(
+ bt_stream_class *stream_class,
+ int64_t stream_id, void *data);
+};
+
+/** CTF message iterator. */
+struct bt_msg_iter;
+
+/**
+ * Creates a CTF message iterator.
+ *
+ * Upon successful completion, the reference count of \p trace is
+ * incremented.
+ *
+ * @param trace Trace to read
+ * @param max_request_sz Maximum buffer size, in bytes, to
+ * request to
+ * bt_msg_iter_medium_ops::request_bytes()
+ * at a time
+ * @param medops Medium operations
+ * @param medops_data User data (passed to medium operations)
+ * @returns New CTF message iterator on
+ * success, or \c NULL on error
+ */
+BT_HIDDEN
+struct bt_msg_iter *bt_msg_iter_create(struct ctf_trace_class *tc,
+ size_t max_request_sz, struct bt_msg_iter_medium_ops medops,
+ void *medops_data);
+
+/**
+ * Destroys a CTF message iterator, freeing all internal resources.
+ *
+ * The registered trace's reference count is decremented.
+ *
+ * @param msg_iter CTF message iterator
+ */
+BT_HIDDEN
+void bt_msg_iter_destroy(struct bt_msg_iter *msg_iter);
+
+/**
+ * Returns the next message from a CTF message iterator.
+ *
+ * Upon successful completion, #BT_MSG_ITER_STATUS_OK is
+ * returned, and the next message is written to \p msg.
+ * In this case, the caller is responsible for calling
+ * bt_message_put() on the returned message.
+ *
+ * If this function returns #BT_MSG_ITER_STATUS_AGAIN, the caller
+ * should make sure that data becomes available to its medium, and
+ * call this function again, until another status is returned.
+ *
+ * @param msg_iter CTF message iterator
+ * @param message Returned message if the function's
+ * return value is #BT_MSG_ITER_STATUS_OK
+ * @returns One of #bt_msg_iter_status values
+ */
+BT_HIDDEN
+enum bt_msg_iter_status bt_msg_iter_get_next_message(
+ struct bt_msg_iter *notit,
+ bt_self_message_iterator *msg_iter,
+ bt_message **message);
+
+/**
+ * Returns the first packet header and context fields. This function
+ * never needs to call the `borrow_stream()` medium operation because
+ * it does not create packet or event objects.
+ *
+ * @param msg_iter CTF message iterator
+ * @param packet_header_field Packet header field (\c NULL if there's
+ * no packet header field)
+ * @param packet_context_field Packet context field (\c NULL if there's
+ * no packet context field)
+ * @returns One of #bt_msg_iter_status values
+ */
+BT_HIDDEN
+enum bt_msg_iter_status bt_msg_iter_borrow_packet_header_context_fields(
+ struct bt_msg_iter *notit,
+ bt_field **packet_header_field,
+ bt_field **packet_context_field);
+
+struct bt_msg_iter_packet_properties {
+ uint64_t exp_packet_total_size;
+ uint64_t exp_packet_content_size;
+ uint64_t stream_class_id;
+ int64_t data_stream_id;
+
+ struct {
+ uint64_t discarded_events;
+ uint64_t packets;
+ uint64_t beginning_clock;
+ uint64_t end_clock;
+ } snapshots;
+};
+
+BT_HIDDEN
+enum bt_msg_iter_status bt_msg_iter_get_packet_properties(
+ struct bt_msg_iter *notit,
+ struct bt_msg_iter_packet_properties *props);
+
+BT_HIDDEN
+void bt_msg_iter_set_medops_data(struct bt_msg_iter *notit,
+ void *medops_data);
+
+BT_HIDDEN
+enum bt_msg_iter_status bt_msg_iter_seek(
+ struct bt_msg_iter *notit, off_t offset);
+
+/*
+ * Get the current packet's offset in bytes relative to the media's initial
+ * position.
+ */
+BT_HIDDEN
+off_t bt_msg_iter_get_current_packet_offset(
+ struct bt_msg_iter *notit);
+
+/* Get the current packet's size (in bits). */
+BT_HIDDEN
+off_t bt_msg_iter_get_current_packet_size(
+ struct bt_msg_iter *notit);
+
+/*
+ * Resets the iterator so that the next requested medium bytes are
+ * assumed to be the first bytes of a new stream. The first message
+ * which this iterator emits after calling bt_msg_iter_reset() is a
+ * BT_MESSAGE_TYPE_STREAM_BEGINNING one.
+ */
+BT_HIDDEN
+void bt_msg_iter_reset(struct bt_msg_iter *notit);
+
+/*
+ * Notify the iterator that the trace class changed somehow (new
+ * stream/event classes).
+ */
+BT_HIDDEN
+void bt_msg_trace_class_changed(struct bt_msg_iter *notit);
+
+static inline
+const char *bt_msg_iter_medium_status_string(
+ enum bt_msg_iter_medium_status status)
+{
+ switch (status) {
+ case BT_MSG_ITER_MEDIUM_STATUS_EOF:
+ return "BT_MSG_ITER_MEDIUM_STATUS_EOF";
+ case BT_MSG_ITER_MEDIUM_STATUS_AGAIN:
+ return "BT_MSG_ITER_MEDIUM_STATUS_AGAIN";
+ case BT_MSG_ITER_MEDIUM_STATUS_INVAL:
+ return "BT_MSG_ITER_MEDIUM_STATUS_INVAL";
+ case BT_MSG_ITER_MEDIUM_STATUS_ERROR:
+ return "BT_MSG_ITER_MEDIUM_STATUS_ERROR";
+ case BT_MSG_ITER_MEDIUM_STATUS_OK:
+ return "BT_MSG_ITER_MEDIUM_STATUS_OK";
+ default:
+ return "(unknown)";
+ }
+}
+
+static inline
+const char *bt_msg_iter_status_string(
+ enum bt_msg_iter_status status)
+{
+ switch (status) {
+ case BT_MSG_ITER_STATUS_EOF:
+ return "BT_MSG_ITER_STATUS_EOF";
+ case BT_MSG_ITER_STATUS_AGAIN:
+ return "BT_MSG_ITER_STATUS_AGAIN";
+ case BT_MSG_ITER_STATUS_INVAL:
+ return "BT_MSG_ITER_STATUS_INVAL";
+ case BT_MSG_ITER_STATUS_ERROR:
+ return "BT_MSG_ITER_STATUS_ERROR";
+ case BT_MSG_ITER_STATUS_OK:
+ return "BT_MSG_ITER_STATUS_OK";
+ default:
+ return "(unknown)";
+ }
+}
+
+#endif /* CTF_MSG_ITER_H */
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