src/interfaces/serializer.h

/*****************************************************************************\
 *  serializer.h - serializer plugin interface
 *****************************************************************************
 *  Copyright (C) SchedMD LLC.
 *
 *  This file is part of Slurm, a resource management program.
 *  For details, see <https://slurm.schedmd.com/>.
 *  Please also read the included file: DISCLAIMER.
 *
 *  Slurm is free software; you can redistribute it and/or modify it under
 *  the terms of the GNU General Public License as published by the Free
 *  Software Foundation; either version 2 of the License, or (at your option)
 *  any later version.
 *
 *  In addition, as a special exception, the copyright holders give permission
 *  to link the code of portions of this program with the OpenSSL library under
 *  certain conditions as described in each individual source file, and
 *  distribute linked combinations including the two. You must obey the GNU
 *  General Public License in all respects for all of the code used other than
 *  OpenSSL. If you modify file(s) with this exception, you may extend this
 *  exception to your version of the file(s), but you are not obligated to do
 *  so. If you do not wish to do so, delete this exception statement from your
 *  version.  If you delete this exception statement from all source files in
 *  the program, then also delete it here.
 *
 *  Slurm is distributed in the hope that it will be useful, but WITHOUT ANY
 *  WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 *  FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
 *  details.
 *
 *  You should have received a copy of the GNU General Public License along
 *  with Slurm; if not, write to the Free Software Foundation, Inc.,
 *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301  USA.
\*****************************************************************************/

#ifndef _INTERFACES_SERIALIZER_H
#define _INTERFACES_SERIALIZER_H

#include "src/common/data.h"
#include "src/common/macros.h"
#include "src/common/pack.h"

#include "src/interfaces/data_parser.h"

typedef enum {
	SER_FLAGS_NONE = 0, /* defaults to compact currently */
	SER_FLAGS_COMPACT = SLURM_BIT(0),
	SER_FLAGS_PRETTY = SLURM_BIT(1),
	SER_FLAGS_COMPLEX = SLURM_BIT(2), /* Dump Infinity and NaN */
	SER_FLAGS_NO_TAG = SLURM_BIT(3), /* don't dump YAML tags */
	SER_FLAGS_JSON6 = SLURM_BIT(4),
	/* Flags selecting an output layout. At most one may ever be set. */
	SER_FLAGS_LAYOUT_MASK = (SER_FLAGS_COMPACT | SER_FLAGS_PRETTY),
} serializer_flags_t;

typedef enum {
	SER_MIMETYPE_FLAGS_NONE = 0,
	SER_MIMETYPE_FLAGS_OPENAPI = SLURM_BIT(0),
} serializer_mimetype_flags_t;

/* Plugin MIME type arrays end with an entry whose mimetype is NULL. */
typedef struct {
	serializer_mimetype_flags_t flags;
	char *mimetype;
} serializer_mimetype_t;

/*
 * Define common MIME types to make it easier for serializer callers.
 *
 * WARNING: There is no guarantee that plugins for these types
 * will be loaded at any given time.
 *
 * Each must be the primary type of the plugin providing it: the primary is
 * what get_mime_type_array(false) returns and serializer_g_init() matches
 * to hand a plugin its configuration. Compatibility aliases stay registered
 * for inbound requests but must not be named here.
 */
#define MIME_TYPE_YAML "application/yaml" /* RFC9512 */
#define MIME_TYPE_YAML_PLUGIN "serializer/yaml"
#define ENV_CONFIG_YAML "SLURM_YAML"
#define MIME_TYPE_JSON "application/json"
#define MIME_TYPE_JSON_PLUGIN "serializer/json"
#define ENV_CONFIG_JSON "SLURM_JSON"
#define MIME_TYPE_URL_ENCODED "application/x-www-form-urlencoded"
#define MIME_TYPE_URL_ENCODED_PLUGIN "serializer/url-encoded"
#define MIME_TYPE_XJSON_PLUGIN "serializer/xjson"
#define MIME_TYPE_JSON_PATCH "application/json-patch+json" /* RFC6902 */
#define MIME_TYPE_JSON_PATCH_PLUGIN "serializer/json-patch"

/*
 * Serialize data in src into string dest
 * IN/OUT dest - ptr to NULL string ptr to set with output data.
 * 	caller must xfree(dest) if set. Pointer is not changed on failure.
 * IN/OUT length - set with number of bytes written to *dest.
 *	Note: length will not include '\0'
 * IN src - populated data ptr to serialize
 * IN mime_type - serialize data into the given mime_type
 * IN flags - optional flags to specify to serilzier to change presentation of
 * 	data
 * RET SLURM_SUCCESS or error
 */
extern int serialize_g_data_to_string(char **dest, size_t *length, data_t *src,
				      const char *mime_type,
				      serializer_flags_t flags);

/*
 * serialize string in src into data dest
 * IN/OUT dest - ptr to NULL data ptr to set with output data.
 * 	caller must FREE_NULL_DATA(dest) if set.
 * 	serializer/json-patch instead takes the target document in *dest and
 * 	patches it in place, leaving it unchanged on failure.
 * IN src - string to deserialize
 * IN length - number of bytes in src
 * IN mime_type - deserialize data using given mime_type
 * RET SLURM_SUCCESS or error
 *	SLURM_NO_CHANGE_IN_DATA - serializer/json-patch only: a nonempty patch
 *	leaves the document unchanged
 */
extern int serialize_g_string_to_data(data_t **dest, const char *src,
				      size_t length, const char *mime_type);

typedef struct serialize_parse_state_s serialize_parse_state_t;

/*
 * Parse given (potentially partial) string buffer into target struct dst
 * IN/OUT state_ptr - Pointer populated with parsing state
 *	Only populated when src ran out before the parse completed, marking
 *	where the parse stopped. Supply the rest of src and call again with the
 *	same state_ptr to resume. Released and set to NULL once the parse
 *	completes or fails.
 *	Passing a NULL src will always release state_ptr.
 * IN parser - return from data_parser_g_new()
 * IN type - expected data_parser type of obj
 * IN dst - ptr to struct/scalar to populate
 *	This *must* be a pointer to the object and not just a value of the
 *	object.
 * IN dst_bytes - size of object pointed to by dst
 * IN src - string buffer to parse into obj.
 *	[offset, size) will be string to be read.
 *	src offset will be set with how many bytes have been processed
 * IN mime_type - deserialize data using given mime_type
 * RET SLURM_SUCCESS once the parse is complete or stopped waiting on more src
 *	to be supplied (state_ptr populated), or error
 */
extern int serialize_g_parse(serialize_parse_state_t **state_ptr,
			     data_parser_t *parser, data_parser_type_t type,
			     void *dst, ssize_t dst_bytes, buf_t *src,
			     const char *mime_type);

typedef struct serialize_dump_state_s serialize_dump_state_t;

/*
 * Dump given target struct src into fixed size buffer
 * IN/OUT state_ptr - Pointer populated with dumping state
 *	Only populated when ENOSPC is returned, marking where the dump stopped.
 *	Grow dst and call again with the same state_ptr to resume. Released and
 *	set to NULL on every other return.
 *	Passing a NULL dst will always release state_ptr.
 * IN parser - return from data_parser_g_new()
 * IN type - data_parser type of obj
 * IN src - ptr to struct/scalar to dump to data_t
 *	This *must* be a pointer to the object and not just a value of the object.
 * IN src_bytes - size of object pointed to by src
 * IN/OUT dst - buffer to populate with serialized output.
 *	Writes will try to honor the size of the buffer (but may resize it).
 *	Offset to indicate the bytes populated.
 * IN flags - optional flags to specify to serilzier to change presentation of
 *	data
 * RET SLURM_SUCCESS once the dump is complete, ENOSPC if dst was too small to
 *	hold the rest of the dump and it must be resumed, or error
 */
extern int serialize_g_dump(serialize_dump_state_t **state_ptr,
			    data_parser_t *parser, data_parser_type_t type,
			    void *src, ssize_t src_bytes, buf_t *dst,
			    const char *mime_type, serializer_flags_t flags);

/*
 * Check if there is a plugin loaded that can handle the requested mime type
 * RET ptr to best matching mime type or NULL if none can match
 */
extern const char *resolve_mime_type(const char *mime_type,
				     const char **plugin_ptr);

/*
 * Provide a NULL terminated array of registered MIME types.
 * IN openapi - only return types flagged SER_MIMETYPE_FLAGS_OPENAPI when true;
 * otherwise return the primary MIME type per plugin.
 * RET borrowed array, valid until serializer_g_fini()
 * WARNING: serializer_g_init() should not be called after this is called
 */
extern const char **get_mime_type_array(bool openapi);

/*
 * Ensure a plugin is loaded that can handle mime_type.
 */
extern void serializer_required(const char *mime_type);

/*
 * Load and initialize serializer plugins
 *
 * IN config - string with configuration to parse or NULL
 * RET SLURM_SUCCESS or error
 */
extern int serializer_g_init(void);

/*
 * Unload all serializer plugins
 */
extern void serializer_g_fini(void);

#endif