General API structure

From our previous discussions (ref !3 (merged)) it seems like the consensus is to have two API tiers:

• A low-level API mirroring the EDID and DisplayID specs
• A high-level API exposing simple and easy-to-use helpers for common metadata compositors are interested in

How does this translate to a C API?

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There's a related discussion about this in !2 (comment 1311164). The general idea is:

/* Low-level EDID API */

struct di_edid;

struct di_edid *
di_edid_parse(const void *data, size_t size);

void
di_edid_destroy(struct di_edid *edid);

int
di_edid_get_version(const struct di_edid *edid);

int
di_edid_get_revision(const struct di_edid *edid);

void
di_edid_get_vendor_product(const struct di_edid *edid,
			   struct di_edid_vendor_product *vendor_product);

/* etc */

/* Low-level DisplayID API */

struct di_displayid;

struct di_displayid *
di_displayid_parse(const void *data, size_t size);

void
di_displayid_destroy(struct di_displayid *displayid);

/* etc */

/* High-level API (uses low-level APIs internally) */

struct di_info;

struct di_info *
di_info_parse_edid(const void *data, size_t size);

struct di_info *
di_info_parse_displayid(const void *data, size_t size);

void
di_info_destroy(struct di_info *info);

/* Returns the EDID if any */
const struct di_edid *
di_info_get_edid(const struct di_info *info);

/* Returns the DisplayID if any (standalone or embedded in an EDID block) */
const struct di_displayid *
di_info_get_displayid(const struct di_info *info);

/* Returns the serial number string, looking first at the DisplayID if any,
 * falling back to the EDID otherwise. */
char *
di_info_get_serial(const struct di_info *info);

/* etc */