jemalloc/internal/emitter.h

#ifndef JEMALLOC_INTERNAL_EMITTER_H
#define JEMALLOC_INTERNAL_EMITTER_H

#include "jemalloc/internal/ql.h"

typedef enum emitter_output_e emitter_output_t;
enum emitter_output_e {
	emitter_output_json,
	emitter_output_table
};

typedef enum emitter_justify_e emitter_justify_t;
enum emitter_justify_e {
	emitter_justify_left,
	emitter_justify_right,
	/* Not for users; just to pass to internal functions. */
	emitter_justify_none
};

typedef enum emitter_type_e emitter_type_t;
enum emitter_type_e {
	emitter_type_bool,
	emitter_type_int,
	emitter_type_unsigned,
	emitter_type_uint32,
	emitter_type_uint64,
	emitter_type_size,
	emitter_type_ssize,
	emitter_type_string,
	/*
	 * A title is a column title in a table; it's just a string, but it's
	 * not quoted.
	 */
	emitter_type_title,
};

typedef struct emitter_col_s emitter_col_t;
struct emitter_col_s {
	/* Filled in by the user. */
	emitter_justify_t justify;
	int width;
	emitter_type_t type;
	union {
		bool bool_val;
		int int_val;
		unsigned unsigned_val;
		uint32_t uint32_val;
		uint64_t uint64_val;
		size_t size_val;
		ssize_t ssize_val;
		const char *str_val;
	};

	/* Filled in by initialization. */
	ql_elm(emitter_col_t) link;
};

typedef struct emitter_row_s emitter_row_t;
struct emitter_row_s {
	ql_head(emitter_col_t) cols;
};

static inline void
emitter_row_init(emitter_row_t *row) {
	ql_new(&row->cols);
}

static inline void
emitter_col_init(emitter_col_t *col, emitter_row_t *row) {
	ql_elm_new(col, link);
	ql_tail_insert(&row->cols, col, link);
}

typedef struct emitter_s emitter_t;
struct emitter_s {
	emitter_output_t output;
	/* The output information. */
	void (*write_cb)(void *, const char *);
	void *cbopaque;
	int nesting_depth;
	/* True if we've already emitted a value at the given depth. */
	bool item_at_depth;
};

static inline void
emitter_init(emitter_t *emitter, emitter_output_t emitter_output,
    void (*write_cb)(void *, const char *), void *cbopaque) {
	emitter->output = emitter_output;
	emitter->write_cb = write_cb;
	emitter->cbopaque = cbopaque;
	emitter->item_at_depth = false;
	emitter->nesting_depth = 0;
}

/* Internal convenience function.  Write to the emitter the given string. */
JEMALLOC_FORMAT_PRINTF(2, 3)
static inline void
emitter_printf(emitter_t *emitter, const char *format, ...) {
	va_list ap;

	va_start(ap, format);
	malloc_vcprintf(emitter->write_cb, emitter->cbopaque, format, ap);
	va_end(ap);
}

/* Write to the emitter the given string, but only in table mode. */
JEMALLOC_FORMAT_PRINTF(2, 3)
static inline void
emitter_table_printf(emitter_t *emitter, const char *format, ...) {
	if (emitter->output == emitter_output_table) {
		va_list ap;
		va_start(ap, format);
		malloc_vcprintf(emitter->write_cb, emitter->cbopaque, format, ap);
		va_end(ap);
	}
}

static inline void
emitter_gen_fmt(char *out_fmt, size_t out_size, const char *fmt_specifier,
    emitter_justify_t justify, int width) {
	size_t written;
	if (justify == emitter_justify_none) {
		written = malloc_snprintf(out_fmt, out_size,
		    "%%%s", fmt_specifier);
	} else if (justify == emitter_justify_left) {
		written = malloc_snprintf(out_fmt, out_size,
		    "%%-%d%s", width, fmt_specifier);
	} else {
		written = malloc_snprintf(out_fmt, out_size,
		    "%%%d%s", width, fmt_specifier);
	}
	/* Only happens in case of bad format string, which *we* choose. */
	assert(written <  out_size);
}

/*
 * Internal.  Emit the given value type in the relevant encoding (so that the
 * bool true gets mapped to json "true", but the string "true" gets mapped to
 * json "\"true\"", for instance.
 *
 * Width is ignored if justify is emitter_justify_none.
 */
static inline void
emitter_print_value(emitter_t *emitter, emitter_justify_t justify, int width,
    emitter_type_t value_type, const void *value) {
	size_t str_written;
#define BUF_SIZE 256
#define FMT_SIZE 10
	/*
	 * We dynamically generate a format string to emit, to let us use the
	 * snprintf machinery.  This is kinda hacky, but gets the job done
	 * quickly without having to think about the various snprintf edge
	 * cases.
	 */
	char fmt[FMT_SIZE];
	char buf[BUF_SIZE];

#define EMIT_SIMPLE(type, format)					\
	emitter_gen_fmt(fmt, FMT_SIZE, format, justify, width);		\
	emitter_printf(emitter, fmt, *(const type *)value);		\

	switch (value_type) {
	case emitter_type_bool:
		emitter_gen_fmt(fmt, FMT_SIZE, "s", justify, width);
		emitter_printf(emitter, fmt, *(const bool *)value ?
		    "true" : "false");
		break;
	case emitter_type_int:
		EMIT_SIMPLE(int, "d")
		break;
	case emitter_type_unsigned:
		EMIT_SIMPLE(unsigned, "u")
		break;
	case emitter_type_ssize:
		EMIT_SIMPLE(ssize_t, "zd")
		break;
	case emitter_type_size:
		EMIT_SIMPLE(size_t, "zu")
		break;
	case emitter_type_string:
		str_written = malloc_snprintf(buf, BUF_SIZE, "\"%s\"",
		    *(const char *const *)value);
		/*
		 * We control the strings we output; we shouldn't get anything
		 * anywhere near the fmt size.
		 */
		assert(str_written < BUF_SIZE);
		emitter_gen_fmt(fmt, FMT_SIZE, "s", justify, width);
		emitter_printf(emitter, fmt, buf);
		break;
	case emitter_type_uint32:
		EMIT_SIMPLE(uint32_t, FMTu32)
		break;
	case emitter_type_uint64:
		EMIT_SIMPLE(uint64_t, FMTu64)
		break;
	case emitter_type_title:
		EMIT_SIMPLE(char *const, "s");
		break;
	default:
		unreachable();
	}
#undef BUF_SIZE
#undef FMT_SIZE
}


/* Internal functions.  In json mode, tracks nesting state. */
static inline void
emitter_nest_inc(emitter_t *emitter) {
	emitter->nesting_depth++;
	emitter->item_at_depth = false;
}

static inline void
emitter_nest_dec(emitter_t *emitter) {
	emitter->nesting_depth--;
	emitter->item_at_depth = true;
}

static inline void
emitter_indent(emitter_t *emitter) {
	int amount = emitter->nesting_depth;
	const char *indent_str;
	if (emitter->output == emitter_output_json) {
		indent_str = "\t";
	} else {
		amount *= 2;
		indent_str = " ";
	}
	for (int i = 0; i < amount; i++) {
		emitter_printf(emitter, "%s", indent_str);
	}
}

static inline void
emitter_json_key_prefix(emitter_t *emitter) {
	emitter_printf(emitter, "%s\n", emitter->item_at_depth ? "," : "");
	emitter_indent(emitter);
}

static inline void
emitter_begin(emitter_t *emitter) {
	if (emitter->output == emitter_output_json) {
		assert(emitter->nesting_depth == 0);
		emitter_printf(emitter, "{");
		emitter_nest_inc(emitter);
	} else {
		// tabular init
		emitter_printf(emitter, "%s", "");
	}
}

static inline void
emitter_end(emitter_t *emitter) {
	if (emitter->output == emitter_output_json) {
		assert(emitter->nesting_depth == 1);
		emitter_nest_dec(emitter);
		emitter_printf(emitter, "\n}\n");
	}
}

/*
 * Note emits a different kv pair as well, but only in table mode.  Omits the
 * note if table_note_key is NULL.
 */
static inline void
emitter_kv_note(emitter_t *emitter, const char *json_key, const char *table_key,
    emitter_type_t value_type, const void *value,
    const char *table_note_key, emitter_type_t table_note_value_type,
    const void *table_note_value) {
	if (emitter->output == emitter_output_json) {
		assert(emitter->nesting_depth > 0);
		emitter_json_key_prefix(emitter);
		emitter_printf(emitter, "\"%s\": ", json_key);
		emitter_print_value(emitter, emitter_justify_none, -1,
		    value_type, value);
	} else {
		emitter_indent(emitter);
		emitter_printf(emitter, "%s: ", table_key);
		emitter_print_value(emitter, emitter_justify_none, -1,
		    value_type, value);
		if (table_note_key != NULL) {
			emitter_printf(emitter, " (%s: ", table_note_key);
			emitter_print_value(emitter, emitter_justify_none, -1,
			    table_note_value_type, table_note_value);
			emitter_printf(emitter, ")");
		}
		emitter_printf(emitter, "\n");
	}
	emitter->item_at_depth = true;
}

static inline void
emitter_kv(emitter_t *emitter, const char *json_key, const char *table_key,
    emitter_type_t value_type, const void *value) {
	emitter_kv_note(emitter, json_key, table_key, value_type, value, NULL,
	    emitter_type_bool, NULL);
}

static inline void
emitter_json_kv(emitter_t *emitter, const char *json_key,
    emitter_type_t value_type, const void *value) {
	if (emitter->output == emitter_output_json) {
		emitter_kv(emitter, json_key, NULL, value_type, value);
	}
}

static inline void
emitter_table_kv(emitter_t *emitter, const char *table_key,
    emitter_type_t value_type, const void *value) {
	if (emitter->output == emitter_output_table) {
		emitter_kv(emitter, NULL, table_key, value_type, value);
	}
}

static inline void
emitter_dict_begin(emitter_t *emitter, const char *json_key,
    const char *table_header) {
	if (emitter->output == emitter_output_json) {
		emitter_json_key_prefix(emitter);
		emitter_printf(emitter, "\"%s\": {", json_key);
		emitter_nest_inc(emitter);
	} else {
		emitter_indent(emitter);
		emitter_printf(emitter, "%s\n", table_header);
		emitter_nest_inc(emitter);
	}
}

static inline void
emitter_dict_end(emitter_t *emitter) {
	if (emitter->output == emitter_output_json) {
		assert(emitter->nesting_depth > 0);
		emitter_nest_dec(emitter);
		emitter_printf(emitter, "\n");
		emitter_indent(emitter);
		emitter_printf(emitter, "}");
	} else {
		emitter_nest_dec(emitter);
	}
}

static inline void
emitter_json_dict_begin(emitter_t *emitter, const char *json_key) {
	if (emitter->output == emitter_output_json) {
		emitter_dict_begin(emitter, json_key, NULL);
	}
}

static inline void
emitter_json_dict_end(emitter_t *emitter) {
	if (emitter->output == emitter_output_json) {
		emitter_dict_end(emitter);
	}
}

static inline void
emitter_table_dict_begin(emitter_t *emitter, const char *table_key) {
	if (emitter->output == emitter_output_table) {
		emitter_dict_begin(emitter, NULL, table_key);
	}
}

static inline void
emitter_table_dict_end(emitter_t *emitter) {
	if (emitter->output == emitter_output_table) {
		emitter_dict_end(emitter);
	}
}

static inline void
emitter_json_arr_begin(emitter_t *emitter, const char *json_key) {
	if (emitter->output == emitter_output_json) {
		emitter_json_key_prefix(emitter);
		emitter_printf(emitter, "\"%s\": [", json_key);
		emitter_nest_inc(emitter);
	}
}

static inline void
emitter_json_arr_end(emitter_t *emitter) {
	if (emitter->output == emitter_output_json) {
		assert(emitter->nesting_depth > 0);
		emitter_nest_dec(emitter);
		emitter_printf(emitter, "\n");
		emitter_indent(emitter);
		emitter_printf(emitter, "]");
	}
}

static inline void
emitter_json_arr_obj_begin(emitter_t *emitter) {
	if (emitter->output == emitter_output_json) {
		emitter_json_key_prefix(emitter);
		emitter_printf(emitter, "{");
		emitter_nest_inc(emitter);
	}
}

static inline void
emitter_json_arr_obj_end(emitter_t *emitter) {
	if (emitter->output == emitter_output_json) {
		assert(emitter->nesting_depth > 0);
		emitter_nest_dec(emitter);
		emitter_printf(emitter, "\n");
		emitter_indent(emitter);
		emitter_printf(emitter, "}");
	}
}

static inline void
emitter_json_arr_value(emitter_t *emitter, emitter_type_t value_type,
    const void *value) {
	if (emitter->output == emitter_output_json) {
		emitter_json_key_prefix(emitter);
		emitter_print_value(emitter, emitter_justify_none, -1,
		    value_type, value);
	}
}

static inline void
emitter_table_row(emitter_t *emitter, emitter_row_t *row) {
	if (emitter->output != emitter_output_table) {
		return;
	}
	emitter_col_t *col;
	ql_foreach(col, &row->cols, link) {
		emitter_print_value(emitter, col->justify, col->width,
		    col->type, (const void *)&col->bool_val);
	}
	emitter_table_printf(emitter, "\n");
}

#endif /* JEMALLOC_INTERNAL_EMITTER_H */