Update comment to match context API code

[babeltrace.git] / lib / context.c

/*
 * context.c
 *
 * Babeltrace Library
 *
 * Copyright 2011-2012 EfficiOS Inc. and Linux Foundation
 *
 * Author: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
 *         Julien Desfossez <julien.desfossez@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.
 */

#include <babeltrace/babeltrace.h>
#include <babeltrace/context.h>
#include <babeltrace/trace-handle.h>
#include <babeltrace/trace-handle-internal.h>
#include <babeltrace/trace-collection.h>
#include <babeltrace/format.h>
#include <stdlib.h>

#include <fts.h>
#include <fcntl.h> /* For O_RDONLY */

/* TODO ybrosseau: should be hidden in the CTF format */
#include <babeltrace/ctf/types.h> /* for ctf_move_pos_slow */

#include <glib.h>

struct bt_context *bt_context_create(void)
{
	struct bt_context *ctx;

	ctx = g_new0(struct bt_context, 1);
	ctx->refcount = 1;
	/* Negative handle id are errors. */
	ctx->last_trace_handle_id = 0;

	/* Instanciate the trace handle container */
	ctx->trace_handles = g_hash_table_new_full(g_direct_hash,
				g_direct_equal, NULL,
				(GDestroyNotify) bt_trace_handle_destroy);

	ctx->tc = g_new0(struct trace_collection, 1);
	init_trace_collection(ctx->tc);

	return ctx;
}

int bt_context_add_trace(struct bt_context *ctx, const char *path,
		const char *format_str)
{
	struct trace_descriptor *td;
	struct format *fmt;
	struct bt_trace_handle *handle;

	fmt = bt_lookup_format(g_quark_from_string(format_str));
	td = fmt->open_trace(path, O_RDONLY,
			     ctf_move_pos_slow, NULL);
	if (!td) {
		fprintf(stdout, "[error] [Context] Cannot Open_trace of the format %s .\n\n",
				path);
		return 0;
	}

	/* Create an handle for the trace */
	handle = bt_trace_handle_create(ctx);
	if (handle < 0) {
		fprintf(stdout, "[error] [Context] Creating trace handle %s .\n\n",
				path);
		return 0;
	}
	handle->format = fmt;
	handle->td = td;
	strncpy(handle->path, path, PATH_MAX);
	handle->path[PATH_MAX - 1] = '\0';

	/* Add new handle to container */
	g_hash_table_insert(ctx->trace_handles,
		(gpointer) (unsigned long) handle->id,
		handle);
	trace_collection_add(ctx->tc, td);
	return handle->id;
}

/*
 * Unable to open toplevel: failure.
 * Unable to open some subdirectory or file: warn and continue;
 */
int bt_context_add_traces(struct bt_context *ctx, const char *path,
		const char *format_str)
{
	FTS *tree;
	FTSENT *node;
	GArray *trace_ids;
	char lpath[PATH_MAX];
	char * const paths[2] = { lpath, NULL };
	int ret;

	/*
	 * Need to copy path, because fts_open can change it.
	 * It is the pointer array, not the strings, that are constant.
	 */
	strncpy(lpath, path, PATH_MAX);
	lpath[PATH_MAX - 1] = '\0';

	tree = fts_open(paths, FTS_NOCHDIR | FTS_LOGICAL, 0);
	if (tree == NULL) {
		fprintf(stdout, "[error] Cannot traverse \"%s\" for reading.\n\n",
				path);
		return -EINVAL;
	}

	trace_ids = g_array_new(FALSE, TRUE, sizeof(int));

	while ((node = fts_read(tree))) {
		int dirfd, metafd;

		if (!(node->fts_info & FTS_D))
			continue;

		dirfd = open(node->fts_accpath, 0);
		if (dirfd < 0) {
			fprintf(stdout, "[warning] unable to open trace "
				"directory file descriptor.\n");
			continue;
		}
		metafd = openat(dirfd, "metadata", O_RDONLY);
		if (metafd < 0) {
			ret = close(dirfd);
			if (ret < 0) {
				perror("close");
				goto error;
			}
		} else {
			int trace_id;

			ret = close(metafd);
			if (ret < 0) {
				perror("close");
				goto error;
			}
			ret = close(dirfd);
			if (ret < 0) {
				perror("close");
				goto error;
			}

			trace_id = bt_context_add_trace(ctx,
				node->fts_accpath, format_str);
			if (trace_id < 0) {
				fprintf(stdout, "[warning] CTX opening trace \"%s\"from %s "
					"for reading.\n\n", node->fts_accpath, path);
				continue;
			}
			g_array_append_val(trace_ids, trace_id);
		}
	}

	g_array_free(trace_ids, TRUE);
	return 0;

error:
	return ret;
}

void bt_context_remove_trace(struct bt_context *ctx, int handle_id)
{
	struct bt_trace_handle *handle;

	handle = g_hash_table_lookup(ctx->trace_handles,
		(gpointer) (unsigned long) handle_id);
	assert(handle != NULL);

	/* Remove from containers */
	trace_collection_remove(ctx->tc, handle->td);
	g_hash_table_remove(ctx->trace_handles,
		(gpointer) (unsigned long) handle_id);

	/* Close the trace */
	handle->format->close_trace(handle->td);

	/* Destory the handle */
	bt_trace_handle_destroy(handle);
}

static
void bt_context_destroy(struct bt_context *ctx)
{
	finalize_trace_collection(ctx->tc);

	/* Remote all traces. The g_hash_table_destroy will call
	 * bt_trace_handle_destroy on each elements.
	 */
	g_hash_table_destroy(ctx->trace_handles);

	/* ctx->tc should always be valid */
	assert(ctx->tc != NULL);
	g_free(ctx->tc);
	g_free(ctx);
}

void bt_context_get(struct bt_context *ctx)
{
	ctx->refcount++;
}

void bt_context_put(struct bt_context *ctx)
{
	ctx->refcount--;
	if (ctx->refcount == 0)
		bt_context_destroy(ctx);
}