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Diffstat (limited to 'src/shared/json.h')
| -rw-r--r-- | src/shared/json.h | 285 |
1 files changed, 285 insertions, 0 deletions
diff --git a/src/shared/json.h b/src/shared/json.h new file mode 100644 index 0000000..f8e035c --- /dev/null +++ b/src/shared/json.h @@ -0,0 +1,285 @@ +/* SPDX-License-Identifier: LGPL-2.1+ */ +#pragma once + +#include <stdbool.h> +#include <stddef.h> +#include <stdint.h> + +#include "macro.h" +#include "string-util.h" +#include "util.h" + +/* + In case you wonder why we have our own JSON implementation, here are a couple of reasons why this implementation has + benefits over various other implementatins: + + - We need support for 64bit signed and unsigned integers, i.e. the full 64,5bit range of -9223372036854775808…18446744073709551615 + - All our variants are immutable after creation + - Special values such as true, false, zero, null, empty strings, empty array, empty objects require zero dynamic memory + - Progressive parsing + - Our integer/real type implicitly converts, but only if that's safe and loss-lessly possible + - There's a "builder" for putting together objects easily in varargs function calls + - There's a "dispatcher" for mapping objects to C data structures + - Every variant optionally carries parsing location information, which simplifies debugging and parse log error generation + - Formatter has color, line, column support + + Limitations: + - Doesn't allow embedded NUL in strings + - Can't store integers outside of the -9223372036854775808…18446744073709551615 range (it will use 'long double' for + values outside this range, which is lossy) + - Can't store negative zero (will be treated identical to positive zero, and not retained across serialization) + - Can't store non-integer numbers that can't be stored in "long double" losslessly + - Allows creation and parsing of objects with duplicate keys. The "dispatcher" will refuse them however. This means + we can parse and pass around such objects, but will carefully refuse them when we convert them into our own data. + + (These limitations should be pretty much in line with those of other JSON implementations, in fact might be less + limiting in most cases even.) +*/ + +typedef struct JsonVariant JsonVariant; + +typedef enum JsonVariantType { + JSON_VARIANT_STRING, + JSON_VARIANT_INTEGER, + JSON_VARIANT_UNSIGNED, + JSON_VARIANT_REAL, + JSON_VARIANT_NUMBER, /* This a pseudo-type: we can never create variants of this type, but we use it as wildcard check for the above three types */ + JSON_VARIANT_BOOLEAN, + JSON_VARIANT_ARRAY, + JSON_VARIANT_OBJECT, + JSON_VARIANT_NULL, + _JSON_VARIANT_TYPE_MAX, + _JSON_VARIANT_TYPE_INVALID = -1 +} JsonVariantType; + +int json_variant_new_stringn(JsonVariant **ret, const char *s, size_t n); +int json_variant_new_integer(JsonVariant **ret, intmax_t i); +int json_variant_new_unsigned(JsonVariant **ret, uintmax_t u); +int json_variant_new_real(JsonVariant **ret, long double d); +int json_variant_new_boolean(JsonVariant **ret, bool b); +int json_variant_new_array(JsonVariant **ret, JsonVariant **array, size_t n); +int json_variant_new_array_bytes(JsonVariant **ret, const void *p, size_t n); +int json_variant_new_array_strv(JsonVariant **ret, char **l); +int json_variant_new_object(JsonVariant **ret, JsonVariant **array, size_t n); +int json_variant_new_null(JsonVariant **ret); + +static inline int json_variant_new_string(JsonVariant **ret, const char *s) { + return json_variant_new_stringn(ret, s, strlen_ptr(s)); +} + +JsonVariant *json_variant_ref(JsonVariant *v); +JsonVariant *json_variant_unref(JsonVariant *v); +void json_variant_unref_many(JsonVariant **array, size_t n); + +DEFINE_TRIVIAL_CLEANUP_FUNC(JsonVariant *, json_variant_unref); + +const char *json_variant_string(JsonVariant *v); +intmax_t json_variant_integer(JsonVariant *v); +uintmax_t json_variant_unsigned(JsonVariant *v); +long double json_variant_real(JsonVariant *v); +bool json_variant_boolean(JsonVariant *v); + +JsonVariantType json_variant_type(JsonVariant *v); +bool json_variant_has_type(JsonVariant *v, JsonVariantType type); + +static inline bool json_variant_is_string(JsonVariant *v) { + return json_variant_has_type(v, JSON_VARIANT_STRING); +} + +static inline bool json_variant_is_integer(JsonVariant *v) { + return json_variant_has_type(v, JSON_VARIANT_INTEGER); +} + +static inline bool json_variant_is_unsigned(JsonVariant *v) { + return json_variant_has_type(v, JSON_VARIANT_UNSIGNED); +} + +static inline bool json_variant_is_real(JsonVariant *v) { + return json_variant_has_type(v, JSON_VARIANT_REAL); +} + +static inline bool json_variant_is_number(JsonVariant *v) { + return json_variant_has_type(v, JSON_VARIANT_NUMBER); +} + +static inline bool json_variant_is_boolean(JsonVariant *v) { + return json_variant_has_type(v, JSON_VARIANT_BOOLEAN); +} + +static inline bool json_variant_is_array(JsonVariant *v) { + return json_variant_has_type(v, JSON_VARIANT_ARRAY); +} + +static inline bool json_variant_is_object(JsonVariant *v) { + return json_variant_has_type(v, JSON_VARIANT_OBJECT); +} + +static inline bool json_variant_is_null(JsonVariant *v) { + return json_variant_has_type(v, JSON_VARIANT_NULL); +} + +bool json_variant_is_negative(JsonVariant *v); + +size_t json_variant_elements(JsonVariant *v); +JsonVariant *json_variant_by_index(JsonVariant *v, size_t index); +JsonVariant *json_variant_by_key(JsonVariant *v, const char *key); +JsonVariant *json_variant_by_key_full(JsonVariant *v, const char *key, JsonVariant **ret_key); + +bool json_variant_equal(JsonVariant *a, JsonVariant *b); + +struct json_variant_foreach_state { + JsonVariant *variant; + size_t idx; +}; + +#define JSON_VARIANT_ARRAY_FOREACH(i, v) \ + for (struct json_variant_foreach_state _state = { (v), 0 }; \ + _state.idx < json_variant_elements(_state.variant) && \ + ({ i = json_variant_by_index(_state.variant, _state.idx); \ + true; }); \ + _state.idx++) + +#define JSON_VARIANT_OBJECT_FOREACH(k, e, v) \ + for (struct json_variant_foreach_state _state = { (v), 0 }; \ + _state.idx < json_variant_elements(_state.variant) && \ + ({ k = json_variant_by_index(_state.variant, _state.idx); \ + e = json_variant_by_index(_state.variant, _state.idx + 1); \ + true; }); \ + _state.idx += 2) + +int json_variant_get_source(JsonVariant *v, const char **ret_source, unsigned *ret_line, unsigned *ret_column); + +typedef enum JsonFormatFlags { + JSON_FORMAT_NEWLINE = 1 << 0, /* suffix with newline */ + JSON_FORMAT_PRETTY = 1 << 1, /* add internal whitespace to appeal to human readers */ + JSON_FORMAT_COLOR = 1 << 2, /* insert ANSI color sequences */ + JSON_FORMAT_COLOR_AUTO = 1 << 3, /* insert ANSI color sequences if colors_enabled() says so */ + JSON_FORMAT_SOURCE = 1 << 4, /* prefix with source filename/line/column */ + JSON_FORMAT_SSE = 1 << 5, /* prefix/suffix with W3C server-sent events */ + JSON_FORMAT_SEQ = 1 << 6, /* prefix/suffix with RFC 7464 application/json-seq */ +} JsonFormatFlags; + +int json_variant_format(JsonVariant *v, JsonFormatFlags flags, char **ret); +void json_variant_dump(JsonVariant *v, JsonFormatFlags flags, FILE *f, const char *prefix); + +int json_parse(const char *string, JsonVariant **ret, unsigned *ret_line, unsigned *ret_column); +int json_parse_continue(const char **p, JsonVariant **ret, unsigned *ret_line, unsigned *ret_column); +int json_parse_file(FILE *f, const char *path, JsonVariant **ret, unsigned *ret_line, unsigned *ret_column); + +enum { + _JSON_BUILD_STRING, + _JSON_BUILD_INTEGER, + _JSON_BUILD_UNSIGNED, + _JSON_BUILD_REAL, + _JSON_BUILD_BOOLEAN, + _JSON_BUILD_ARRAY_BEGIN, + _JSON_BUILD_ARRAY_END, + _JSON_BUILD_OBJECT_BEGIN, + _JSON_BUILD_OBJECT_END, + _JSON_BUILD_PAIR, + _JSON_BUILD_PAIR_CONDITION, + _JSON_BUILD_NULL, + _JSON_BUILD_VARIANT, + _JSON_BUILD_LITERAL, + _JSON_BUILD_STRV, + _JSON_BUILD_MAX, +}; + +#define JSON_BUILD_STRING(s) _JSON_BUILD_STRING, ({ const char *_x = s; _x; }) +#define JSON_BUILD_INTEGER(i) _JSON_BUILD_INTEGER, ({ intmax_t _x = i; _x; }) +#define JSON_BUILD_UNSIGNED(u) _JSON_BUILD_UNSIGNED, ({ uintmax_t _x = u; _x; }) +#define JSON_BUILD_REAL(d) _JSON_BUILD_REAL, ({ long double _x = d; _x; }) +#define JSON_BUILD_BOOLEAN(b) _JSON_BUILD_BOOLEAN, ({ bool _x = b; _x; }) +#define JSON_BUILD_ARRAY(...) _JSON_BUILD_ARRAY_BEGIN, __VA_ARGS__, _JSON_BUILD_ARRAY_END +#define JSON_BUILD_OBJECT(...) _JSON_BUILD_OBJECT_BEGIN, __VA_ARGS__, _JSON_BUILD_OBJECT_END +#define JSON_BUILD_PAIR(n, ...) _JSON_BUILD_PAIR, ({ const char *_x = n; _x; }), __VA_ARGS__ +#define JSON_BUILD_PAIR_CONDITION(c, n, ...) _JSON_BUILD_PAIR_CONDITION, ({ bool _x = c; _x; }), ({ const char *_x = n; _x; }), __VA_ARGS__ +#define JSON_BUILD_NULL _JSON_BUILD_NULL +#define JSON_BUILD_VARIANT(v) _JSON_BUILD_VARIANT, ({ JsonVariant *_x = v; _x; }) +#define JSON_BUILD_LITERAL(l) _JSON_BUILD_LITERAL, ({ const char *_x = l; _x; }) +#define JSON_BUILD_STRV(l) _JSON_BUILD_STRV, ({ char **_x = l; _x; }) + +int json_build(JsonVariant **ret, ...); +int json_buildv(JsonVariant **ret, va_list ap); + +/* A bitmask of flags used by the dispatch logic. Note that this is a combined bit mask, that is generated from the bit + * mask originally passed into json_dispatch(), the individual bitmask associated with the static JsonDispatch callout + * entry, as well the bitmask specified for json_log() calls */ +typedef enum JsonDispatchFlags { + /* The following three may be set in JsonDispatch's .flags field or the json_dispatch() flags parameter */ + JSON_PERMISSIVE = 1 << 0, /* Shall parsing errors be considered fatal for this property? */ + JSON_MANDATORY = 1 << 1, /* Should existance of this property be mandatory? */ + JSON_LOG = 1 << 2, /* Should the parser log about errors? */ + + /* The following two may be passed into log_json() in addition to the three above */ + JSON_DEBUG = 1 << 3, /* Indicates that this log message is a debug message */ + JSON_WARNING = 1 << 4, /* Indicates that this log message is a warning message */ +} JsonDispatchFlags; + +typedef int (*JsonDispatchCallback)(const char *name, JsonVariant *variant, JsonDispatchFlags flags, void *userdata); + +typedef struct JsonDispatch { + const char *name; + JsonVariantType type; + JsonDispatchCallback callback; + size_t offset; + JsonDispatchFlags flags; +} JsonDispatch; + +int json_dispatch(JsonVariant *v, const JsonDispatch table[], JsonDispatchCallback bad, JsonDispatchFlags flags, void *userdata); + +int json_dispatch_string(const char *name, JsonVariant *variant, JsonDispatchFlags flags, void *userdata); +int json_dispatch_strv(const char *name, JsonVariant *variant, JsonDispatchFlags flags, void *userdata); +int json_dispatch_boolean(const char *name, JsonVariant *variant, JsonDispatchFlags flags, void *userdata); +int json_dispatch_tristate(const char *name, JsonVariant *variant, JsonDispatchFlags flags, void *userdata); +int json_dispatch_variant(const char *name, JsonVariant *variant, JsonDispatchFlags flags, void *userdata); +int json_dispatch_integer(const char *name, JsonVariant *variant, JsonDispatchFlags flags, void *userdata); +int json_dispatch_unsigned(const char *name, JsonVariant *variant, JsonDispatchFlags flags, void *userdata); +int json_dispatch_uint32(const char *name, JsonVariant *variant, JsonDispatchFlags flags, void *userdata); +int json_dispatch_int32(const char *name, JsonVariant *variant, JsonDispatchFlags flags, void *userdata); + +assert_cc(sizeof(uintmax_t) == sizeof(uint64_t)) +#define json_dispatch_uint64 json_dispatch_unsigned + +assert_cc(sizeof(intmax_t) == sizeof(int64_t)) +#define json_dispatch_int64 json_dispatch_integer + +static inline int json_dispatch_level(JsonDispatchFlags flags) { + + /* Did the user request no logging? If so, then never log higher than LOG_DEBUG. Also, if this is marked as + * debug message, then also log at debug level. */ + + if (!(flags & JSON_LOG) || + (flags & JSON_DEBUG)) + return LOG_DEBUG; + + /* Are we invoked in permissive mode, or is this explicitly marked as warning message? Then this should be + * printed at LOG_WARNING */ + if (flags & (JSON_PERMISSIVE|JSON_WARNING)) + return LOG_WARNING; + + /* Otherwise it's an error. */ + return LOG_ERR; +} + +int json_log_internal(JsonVariant *variant, int level, int error, const char *file, int line, const char *func, const char *format, ...) _printf_(7, 8); + +#define json_log(variant, flags, error, ...) \ + ({ \ + int _level = json_dispatch_level(flags), _e = (error); \ + (log_get_max_level() >= LOG_PRI(_level)) \ + ? json_log_internal(variant, _level, _e, __FILE__, __LINE__, __func__, __VA_ARGS__) \ + : -abs(_e); \ + }) + +#define JSON_VARIANT_STRING_CONST(x) _JSON_VARIANT_STRING_CONST(UNIQ, (x)) + +#define _JSON_VARIANT_STRING_CONST(xq, x) \ + ({ \ + _align_(2) static const char UNIQ_T(json_string_const, xq)[] = (x); \ + assert((((uintptr_t) UNIQ_T(json_string_const, xq)) & 1) == 0); \ + (JsonVariant*) ((uintptr_t) UNIQ_T(json_string_const, xq) + 1); \ + }) + +const char *json_variant_type_to_string(JsonVariantType t); +JsonVariantType json_variant_type_from_string(const char *s); |