core/retro_control.h at main · doomsdayone/retro-remote-debug-controller

◆ main retro-remote-debug-controller / core / retro_control.h

9.0 KiB · Objective-C · last changed feat: contract 0.6 — GET/POST /perf, the performance metrics (budget, current frame, windows, zones, raw frames since one, a platform section) and their settings, and /status.capabilities; backend callbacks get_perf and set_perf return allocated JSON (#6) 25 days ago source blame history raw

/* retro_control.h — portable emulator control server (see ../SPEC.md).
 *
 * A retro-platform emulator implements the small read-only backend below and
 * calls retro_control_start(). The shared server (retro_control.c) owns the
 * socket loop, HTTP parsing, PPM/JSON encoding, and control flow
 * (pause / step / free-run). It always binds 127.0.0.1. Contract version is
 * RETRO_CONTROL_CONTRACT (below); the server advertises the highest level whose
 * backend callbacks are all present.
 *
 * Integration is three calls in the emulator's main loop:
 *   retro_control_service();                 // once per iteration (cheap)
 *   if (!retro_control_running()) { idle; }  // gate advancing the machine
 *   ... run one instruction / frame ...
 *   if (frame_completed) retro_control_on_frame();
 *
 * Threading: the server runs on its own thread but never touches machine state
 * there. State-reading endpoints (/mem, /regs, /screenshot) are executed inside
 * retro_control_service() ON THE EMULATOR THREAD, so every read is consistent.
 * The backend callbacks are therefore called from the emulator thread (except
 * get_frame_count, which the server may also read for /status — make it a plain
 * atomic-ish counter read).
 */
#ifndef RETRO_CONTROL_H
#define RETRO_CONTROL_H

#include <stdint.h>
#include <stddef.h>

#ifdef __cplusplus
extern "C" {
#endif

/* Highest contract the core implements. The server advertises the highest level
 * whose backend callbacks are all present: 0.6.0 needs get_perf + set_perf (on
 * top of 0.5); 0.5.0 needs set_pad + get_pad (on top of 0.4); 0.4.0 needs
 * set_pointer + get_pointer (on top of 0.3); 0.3.0 needs inject_key +
 * write_mem + capture_audio; 0.2.0 needs inject_key; else 0.1.0. Keeps a
 * partial backend honest. /status.capabilities lists each group a backend
 * serves whatever level it reaches, so a client can ask for one directly. */
#define RETRO_CONTROL_CONTRACT "0.6.0"

/* Native framebuffer pixel layout; the server swizzles to PPM RGB. */
typedef enum {
    RETRO_PIX_RGB888 = 0,   /* 3 bytes/px: R,G,B                       */
    RETRO_PIX_RGBA8888,     /* 4 bytes/px: R,G,B,A                     */
    RETRO_PIX_BGRA8888      /* 4 bytes/px: B,G,R,A (x16 framebuffer)   */
} retro_pix_fmt_t;

typedef struct {
    const uint8_t *pixels;  /* start of the current complete frame     */
    int width;
    int height;
    retro_pix_fmt_t fmt;
} retro_framebuffer_t;

/* Key action for inject_key (0.2). */
typedef enum {
    RETRO_KEY_TAP  = 0,   /* press then release */
    RETRO_KEY_DOWN = 1,   /* press / hold       */
    RETRO_KEY_UP   = 2    /* release            */
} retro_key_action_t;

/* The emulator implements these. Any may be NULL: the matching endpoint then
 * returns 501 Not Implemented. */
typedef struct retro_control_backend {
    const char *platform;   /* "x16" | "neo6502" | "agon" | ...        */
    const char *emulator;   /* human name, e.g. "x16emu"               */

    /* Debug-read up to min(len, out_cap) bytes at addr into out, side-effect
     * free. bank is the optional bank selector (<0 = current bank). Returns the
     * number of bytes written. */
    uint32_t (*read_mem)(uint32_t addr, int32_t bank, uint32_t len,
                         uint8_t *out, uint32_t out_cap);

    /* Write a JSON object of registers into buf (NUL-terminated). */
    void (*get_regs_json)(char *buf, size_t cap);

    /* Report the current complete-frame framebuffer. */
    void (*get_framebuffer)(retro_framebuffer_t *out);

    /* Monotonic completed-frame counter. */
    uint64_t (*get_frame_count)(void);

    /* 0.2: inject a key. is_text=1 => `value` is a character code point;
     * is_text=0 => `value` is a raw platform key code. `action` is a
     * retro_key_action_t. Return 1 on success, 0 if unmappable (server -> 400).
     * NULL => /key returns 501 and the server advertises contract 0.1.0. */
    int (*inject_key)(int is_text, uint32_t value, int action);

    /* 0.2: soft/cold reset the machine. NULL => /reset returns 501. */
    void (*reset)(void);

    /* 0.3: write len bytes from `in` at addr (debug/state poke; bank<0 =
     * current). Intended for RAM/state — I/O-register writes may trigger device
     * side effects. Return bytes written. NULL => POST /mem returns 501. */
    uint32_t (*write_mem)(uint32_t addr, int32_t bank, uint32_t len,
                          const uint8_t *in);

    /* 0.3: drain up to `cap` interleaved signed-16-bit audio samples the
     * emulator has synthesised since the last call into `out`; set *rate and
     * *channels; set *dropped to samples lost to overflow since the last drain.
     * Return the number of int16 samples written. NULL => /audio returns 501. */
    uint32_t (*capture_audio)(int16_t *out, uint32_t cap,
                              int *rate, int *channels, uint32_t *dropped);

    /* 0.4: inject a pointer (mouse) move/click through the platform's native
     * pointer path. `absolute` nonzero => (x,y) are absolute pointer
     * coordinates (framebuffer/pointer space); zero => (x,y) are relative
     * deltas applied to the current position. `buttons` is a bitmask
     * (bit0 = primary, bit1 = secondary), or -1 to leave the button state
     * unchanged (a pure move). Return 1 on success, 0 if the platform has no
     * pointer (server -> 400). NULL => POST /pointer returns 501. */
    int (*set_pointer)(int absolute, int32_t x, int32_t y, int buttons);

    /* 0.4: report the current pointer position and button bitmask (same
     * semantics as set_pointer's `buttons`). Return 1 on success (values
     * written), 0 if no pointer is available. NULL => GET /pointer returns 501. */
    int (*get_pointer)(int32_t *x, int32_t *y, int *buttons);

    /* 0.5: present a virtual game controller at `index` and set what is held.
     *
     * `buttons` is the canonical mask (SPEC "Canonical button layout"): bit0
     * LEFT, 1 RIGHT, 2 UP, 3 DOWN, 4 A, 5 B, 6 X, 7 Y, 8 START, 9 SELECT,
     * 10 L, 11 R -- the SNES/Neo6502 native order. A backend whose hardware
     * disagrees converts here, so a test never learns which machine it is on.
     * -1 leaves the mask unchanged.
     *
     * `connected` is 1 to present the pad, 0 to unplug it, -1 to leave the
     * presence unchanged. Unplugging is testable behaviour in its own right:
     * a program that asks "is a pad there" before offering two-player needs
     * both answers.
     *
     * A pad is a LEVEL, not an event -- the state persists across frames until
     * changed, unlike inject_key's TAP.
     *
     * MUST drive the same path a real pad takes. On an emulator reading SDL
     * joysticks that means presenting a virtual device the existing read path
     * picks up, NOT calling into SDL: headless CI has no joystick, which is
     * the case this exists for.
     *
     * Return 1 on success, 0 if the platform has no controller support
     * (server -> 400). NULL => POST /pad returns 501. */
    int (*set_pad)(int index, int buttons, int connected);

    /* 0.5: report a pad's presence and held mask (same layout as set_pad).
     * Return 1 on success (values written), 0 if unsupported. NULL => GET /pad
     * returns 501. */
    int (*get_pad)(int index, int *buttons, int *connected);

    /* 0.6: the performance metrics, as the JSON body of GET /perf (SPEC
     * "GET /perf"). `query` is the request's raw query string ("" for none:
     * windows=, zones=, frames=, since=), for the backend to read. Return a
     * malloc'd NUL-terminated string the server frees, or NULL on failure
     * (server -> 500). Called on the emulator thread, so the metrics are read
     * at a frame/instruction boundary like /mem. NULL => GET /perf returns 501
     * and the server does not advertise 0.6.0. */
    char *(*get_perf)(const char *query);

    /* 0.6: apply a POST /perf settings body (a JSON object, NUL-terminated;
     * SPEC "POST /perf"). Set *status to 200, or 400 for a body the backend
     * cannot apply, and return a malloc'd JSON response the server frees (for
     * 200, the settings as they now stand; for 400, {"error":...}). NULL
     * return => 500. NULL callback => POST /perf returns 501. */
    char *(*set_perf)(const char *body, int *status);
} retro_control_backend_t;

/* Start the server thread bound to 127.0.0.1:port. Non-blocking; 0 on success,
 * negative on error. backend must outlive the server. */
int  retro_control_start(int port, const retro_control_backend_t *backend);

/* Drain a pending control request. Call once per main-loop iteration, at an
 * instruction/frame boundary. Cheap no-op when idle and when control is off. */
void retro_control_service(void);

/* Nonzero => the machine should advance this iteration. Returns 1 always when
 * control is off or the machine is free-running; 0 when paused with no steps
 * left. */
int  retro_control_running(void);

/* Call when a video frame completes. Drives /step (decrements the step budget,
 * halts and answers when it reaches zero). No-op when control is off. */
void retro_control_on_frame(void);

/* Stop the server (optional; process exit is fine too). */
void retro_control_stop(void);

#ifdef __cplusplus
}
#endif

#endif /* RETRO_CONTROL_H */

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1	/* retro_control.h — portable emulator control server (see ../SPEC.md).
2	*
3	* A retro-platform emulator implements the small read-only backend below and
4	* calls retro_control_start(). The shared server (retro_control.c) owns the
5	* socket loop, HTTP parsing, PPM/JSON encoding, and control flow
6	* (pause / step / free-run). It always binds 127.0.0.1. Contract version is
7	* RETRO_CONTROL_CONTRACT (below); the server advertises the highest level whose
8	* backend callbacks are all present.
9	*
10	* Integration is three calls in the emulator's main loop:
11	* retro_control_service(); // once per iteration (cheap)
12	* if (!retro_control_running()) { idle; } // gate advancing the machine
13	* ... run one instruction / frame ...
14	* if (frame_completed) retro_control_on_frame();
15	*
16	* Threading: the server runs on its own thread but never touches machine state
17	* there. State-reading endpoints (/mem, /regs, /screenshot) are executed inside
18	* retro_control_service() ON THE EMULATOR THREAD, so every read is consistent.
19	* The backend callbacks are therefore called from the emulator thread (except
20	* get_frame_count, which the server may also read for /status — make it a plain
21	* atomic-ish counter read).
22	*/
23	#ifndef RETRO_CONTROL_H
24	#define RETRO_CONTROL_H
25
26	#include <stdint.h>
27	#include <stddef.h>
28
29	#ifdef __cplusplus
30	extern "C" {
31	#endif
32
33	/* Highest contract the core implements. The server advertises the highest level
34	* whose backend callbacks are all present: 0.6.0 needs get_perf + set_perf (on
35	* top of 0.5); 0.5.0 needs set_pad + get_pad (on top of 0.4); 0.4.0 needs
36	* set_pointer + get_pointer (on top of 0.3); 0.3.0 needs inject_key +
37	* write_mem + capture_audio; 0.2.0 needs inject_key; else 0.1.0. Keeps a
38	* partial backend honest. /status.capabilities lists each group a backend
39	* serves whatever level it reaches, so a client can ask for one directly. */
40	#define RETRO_CONTROL_CONTRACT "0.6.0"
41
42	/* Native framebuffer pixel layout; the server swizzles to PPM RGB. */
43	typedef enum {
44	RETRO_PIX_RGB888 = 0, /* 3 bytes/px: R,G,B */
45	RETRO_PIX_RGBA8888, /* 4 bytes/px: R,G,B,A */
46	RETRO_PIX_BGRA8888 /* 4 bytes/px: B,G,R,A (x16 framebuffer) */
47	} retro_pix_fmt_t;
48
49	typedef struct {
50	const uint8_t pixels; / start of the current complete frame */
51	int width;
52	int height;
53	retro_pix_fmt_t fmt;
54	} retro_framebuffer_t;
55
56	/* Key action for inject_key (0.2). */
57	typedef enum {
58	RETRO_KEY_TAP = 0, /* press then release */
59	RETRO_KEY_DOWN = 1, /* press / hold */
60	RETRO_KEY_UP = 2 /* release */
61	} retro_key_action_t;
62
63	/* The emulator implements these. Any may be NULL: the matching endpoint then
64	* returns 501 Not Implemented. */
65	typedef struct retro_control_backend {
66	const char platform; / "x16" \| "neo6502" \| "agon" \| ... */
67	const char emulator; / human name, e.g. "x16emu" */
68
69	/* Debug-read up to min(len, out_cap) bytes at addr into out, side-effect
70	* free. bank is the optional bank selector (<0 = current bank). Returns the
71	* number of bytes written. */
72	uint32_t (*read_mem)(uint32_t addr, int32_t bank, uint32_t len,
73	uint8_t *out, uint32_t out_cap);
74
75	/* Write a JSON object of registers into buf (NUL-terminated). */
76	void (get_regs_json)(char buf, size_t cap);
77
78	/* Report the current complete-frame framebuffer. */
79	void (get_framebuffer)(retro_framebuffer_t out);
80
81	/* Monotonic completed-frame counter. */
82	uint64_t (*get_frame_count)(void);
83
84	/* 0.2: inject a key. is_text=1 => `value` is a character code point;
85	* is_text=0 => `value` is a raw platform key code. `action` is a
86	* retro_key_action_t. Return 1 on success, 0 if unmappable (server -> 400).
87	* NULL => /key returns 501 and the server advertises contract 0.1.0. */
88	int (*inject_key)(int is_text, uint32_t value, int action);
89
90	/* 0.2: soft/cold reset the machine. NULL => /reset returns 501. */
91	void (*reset)(void);
92
93	/* 0.3: write len bytes from `in` at addr (debug/state poke; bank<0 =
94	* current). Intended for RAM/state — I/O-register writes may trigger device
95	* side effects. Return bytes written. NULL => POST /mem returns 501. */
96	uint32_t (*write_mem)(uint32_t addr, int32_t bank, uint32_t len,
97	const uint8_t *in);
98
99	/* 0.3: drain up to `cap` interleaved signed-16-bit audio samples the
100	* emulator has synthesised since the last call into `out`; set *rate and
101	* channels; set dropped to samples lost to overflow since the last drain.
102	* Return the number of int16 samples written. NULL => /audio returns 501. */
103	uint32_t (capture_audio)(int16_t out, uint32_t cap,
104	int rate, int channels, uint32_t *dropped);
105
106	/* 0.4: inject a pointer (mouse) move/click through the platform's native
107	* pointer path. `absolute` nonzero => (x,y) are absolute pointer
108	* coordinates (framebuffer/pointer space); zero => (x,y) are relative
109	* deltas applied to the current position. `buttons` is a bitmask
110	* (bit0 = primary, bit1 = secondary), or -1 to leave the button state
111	* unchanged (a pure move). Return 1 on success, 0 if the platform has no
112	* pointer (server -> 400). NULL => POST /pointer returns 501. */
113	int (*set_pointer)(int absolute, int32_t x, int32_t y, int buttons);
114
115	/* 0.4: report the current pointer position and button bitmask (same
116	* semantics as set_pointer's `buttons`). Return 1 on success (values
117	* written), 0 if no pointer is available. NULL => GET /pointer returns 501. */
118	int (get_pointer)(int32_t x, int32_t y, int buttons);
119
120	/* 0.5: present a virtual game controller at `index` and set what is held.
121	*
122	* `buttons` is the canonical mask (SPEC "Canonical button layout"): bit0
123	* LEFT, 1 RIGHT, 2 UP, 3 DOWN, 4 A, 5 B, 6 X, 7 Y, 8 START, 9 SELECT,
124	* 10 L, 11 R -- the SNES/Neo6502 native order. A backend whose hardware
125	* disagrees converts here, so a test never learns which machine it is on.
126	* -1 leaves the mask unchanged.
127	*
128	* `connected` is 1 to present the pad, 0 to unplug it, -1 to leave the
129	* presence unchanged. Unplugging is testable behaviour in its own right:
130	* a program that asks "is a pad there" before offering two-player needs
131	* both answers.
132	*
133	* A pad is a LEVEL, not an event -- the state persists across frames until
134	* changed, unlike inject_key's TAP.
135	*
136	* MUST drive the same path a real pad takes. On an emulator reading SDL
137	* joysticks that means presenting a virtual device the existing read path
138	* picks up, NOT calling into SDL: headless CI has no joystick, which is
139	* the case this exists for.
140	*
141	* Return 1 on success, 0 if the platform has no controller support
142	* (server -> 400). NULL => POST /pad returns 501. */
143	int (*set_pad)(int index, int buttons, int connected);
144
145	/* 0.5: report a pad's presence and held mask (same layout as set_pad).
146	* Return 1 on success (values written), 0 if unsupported. NULL => GET /pad
147	* returns 501. */
148	int (get_pad)(int index, int buttons, int *connected);
149
150	/* 0.6: the performance metrics, as the JSON body of GET /perf (SPEC
151	* "GET /perf"). `query` is the request's raw query string ("" for none:
152	* windows=, zones=, frames=, since=), for the backend to read. Return a
153	* malloc'd NUL-terminated string the server frees, or NULL on failure
154	* (server -> 500). Called on the emulator thread, so the metrics are read
155	* at a frame/instruction boundary like /mem. NULL => GET /perf returns 501
156	* and the server does not advertise 0.6.0. */
157	char (get_perf)(const char *query);
158
159	/* 0.6: apply a POST /perf settings body (a JSON object, NUL-terminated;
160	* SPEC "POST /perf"). Set *status to 200, or 400 for a body the backend
161	* cannot apply, and return a malloc'd JSON response the server frees (for
162	* 200, the settings as they now stand; for 400, {"error":...}). NULL
163	* return => 500. NULL callback => POST /perf returns 501. */
164	char (set_perf)(const char body, int status);
165	} retro_control_backend_t;
166
167	/* Start the server thread bound to 127.0.0.1:port. Non-blocking; 0 on success,
168	* negative on error. backend must outlive the server. */
169	int retro_control_start(int port, const retro_control_backend_t *backend);
170
171	/* Drain a pending control request. Call once per main-loop iteration, at an
172	* instruction/frame boundary. Cheap no-op when idle and when control is off. */
173	void retro_control_service(void);
174
175	/* Nonzero => the machine should advance this iteration. Returns 1 always when
176	* control is off or the machine is free-running; 0 when paused with no steps
177	* left. */
178	int retro_control_running(void);
179
180	/* Call when a video frame completes. Drives /step (decrements the step budget,
181	* halts and answers when it reaches zero). No-op when control is off. */
182	void retro_control_on_frame(void);
183
184	/* Stop the server (optional; process exit is fine too). */
185	void retro_control_stop(void);
186
187	#ifdef __cplusplus
188	}
189	#endif
190
191	#endif /* RETRO_CONTROL_H */

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