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fu/c/jsonfmt.c
Yorhel 2aaec6a218 pg: Add json, jsonb, jsonpath support 
NOW we're really getting to the part where this module is more awesome
than DBD::Pg.

(When I started working on this module I was expecting that the Postgres
binary protocol would send jsonb in a binary format as well and that I'd
be duplicating parts of the JSON parser/formatter to make that work, but
it turns out that Postgres just uses plain json for exchange. Saves me
some trouble, I guess)
2025-02-08 15:16:47 +01:00

316 lines
11 KiB
C
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typedef struct {
fustr *out;
UV depth;
int canon;
int pretty; /* <0 when disabled, current nesting level otherwise */
} fujson_fmt_ctx;
static void fujson_fmt(pTHX_ fujson_fmt_ctx *, SV *);
static void fujson_fmt_indent(pTHX_ fujson_fmt_ctx *ctx) {
if (ctx->pretty >= 0) {
char *buf = fustr_write_buf(ctx->out, 1 + ctx->pretty*3);
*buf = '\n';
memset(buf+1, ' ', ctx->pretty*3);
}
}
static void fujson_fmt_str(pTHX_ fujson_fmt_ctx *ctx, const char *stri, size_t len, int utf8) {
size_t off = 0, loff;
const unsigned char *str = (const unsigned char *)stri;
unsigned char *buf;
unsigned char x = 0;
/* Validate entire string for conformance if this is flagged as a utf8
* string, this lets us be lazy further on.
* Commenting this out doubles the performance for formatting unicode
* strings, I suspect there's room for optimizations in
* is_c9strict_utf8_string(). */
if (utf8 && !is_c9strict_utf8_string(str, len)) {
croak("invalid codepoint encountered in string, cannot format to JSON");
}
fustr_write_ch(ctx->out, '\"');
fustr_reserve(ctx->out, len);
while (off < len) {
/* Fast path: no escaping needed */
loff = off;
if (utf8) {
/* we already validated everything >=0x80 */
while (off < len) {
x = str[off];
if (x <= 0x1f || x == '"' || x == '\\' || x == 0x7f) break;
off++;
}
} else {
/* binary strings need special handling for >=0x80 */
while (off < len) {
x = str[off];
if (x <= 0x1f || x == '"' || x == '\\' || x >= 0x7f) break;
off++;
}
}
fustr_write(ctx->out, (char *)str+loff, off-loff);
if (off < len) { /* early break, which means current byte needs special processing */
switch (x) {
case '"': fustr_write(ctx->out, "\\\"", 2); break;
case '\\': fustr_write(ctx->out, "\\\\", 2); break;
case 0x08: fustr_write(ctx->out, "\\b", 2); break;
case 0x09: fustr_write(ctx->out, "\\t", 2); break;
case 0x0a: fustr_write(ctx->out, "\\n", 2); break;
case 0x0c: fustr_write(ctx->out, "\\f", 2); break;
case 0x0d: fustr_write(ctx->out, "\\r", 2); break;
default:
if (x < 0x80) {
buf = (unsigned char *)fustr_write_buf(ctx->out, 6);
memcpy(buf, "\\u00", 4);
buf[4] = PL_hexdigit[(x >> 4) & 0x0f];
buf[5] = PL_hexdigit[x & 0x0f];
} else { /* x >= 0x80, !utf8, so encode as 2-byte UTF-8 */
buf = (unsigned char *)fustr_write_buf(ctx->out, 2);
buf[0] = 0xc0 | (x >> 6);
buf[1] = 0x80 | (x & 0x3f);
}
}
off++;
}
}
fustr_write_ch(ctx->out, '\"');
}
static const char fujson_digits[] =
"00010203040506070809"
"10111213141516171819"
"20212223242526272829"
"30313233343536373839"
"40414243444546474849"
"50515253545556575859"
"60616263646566676869"
"70717273747576777879"
"80818283848586878889"
"90919293949596979899";
static void fujson_fmt_int(pTHX_ fujson_fmt_ctx *ctx, SV *val) {
char buf[32];
char *r = buf+31;
int neg = 0;
IV iv;
UV uv;
if (SvIsUV(val)) { /* Why is this macro not documented? */
uv = SvUV_nomg(val);
} else {
iv = SvIV_nomg(val);
neg = iv < 0;
uv = neg ? -iv : iv;
}
if (uv == 0) {
fustr_write_ch(ctx->out, '0');
return;
}
while (uv >= 10) {
r -= 2;
memcpy(r, fujson_digits + ((uv % 100)<<1), 2);
uv /= 100;
}
if (uv > 0) *(--r) = '0' + (uv % 10);
if (neg) *(--r) = '-';
fustr_write(ctx->out, r, 31 - (r - buf));
}
static void fujson_fmt_av(pTHX_ fujson_fmt_ctx *ctx, AV *av) {
int i, len = av_count(av);
fustr_write_ch(ctx->out, '[');
ctx->pretty++;
for (i=0; i<len; i++) {
if (i) fustr_write_ch(ctx->out, ',');
fujson_fmt_indent(aTHX_ ctx);
SV **sv = av_fetch(av, i, 0);
if (sv) fujson_fmt(aTHX_ ctx, *sv); /* sv will have magic if av is tied, but fujson_fmt() handles that. */
else fustr_write(ctx->out, "null", 4);
}
ctx->pretty--;
if (i) fujson_fmt_indent(aTHX_ ctx);
fustr_write_ch(ctx->out, ']');
}
static int fujson_fmt_hvcmp(const void *pa, const void *pb) {
dTHX;
HE *a = *(HE **)pa;
HE *b = *(HE **)pb;
STRLEN alen, blen;
char *astr = HePV(a, alen);
char *bstr = HePV(b, blen);
int autf = HeUTF8(a);
int butf = HeUTF8(b);
if (autf == butf) {
int cmp = memcmp(bstr, astr, alen < blen ? alen : blen);
return cmp != 0 ? cmp : blen < alen ? -1 : blen == alen ? 0 : 1;
}
return autf ? bytes_cmp_utf8((const U8*)bstr, blen, (const U8*)astr, alen)
: -bytes_cmp_utf8((const U8*)astr, alen, (const U8*)bstr, blen);
}
static void fujson_fmt_hvkv(pTHX_ fujson_fmt_ctx *ctx, HV *hv, HE *he, char **hestr) {
STRLEN helen;
if (*hestr) fustr_write_ch(ctx->out, ',');
fujson_fmt_indent(aTHX_ ctx);
*hestr = HePV(he, helen);
fujson_fmt_str(aTHX_ ctx, *hestr, helen, HeUTF8(he));
if (ctx->pretty > 0) fustr_write(ctx->out, " : ", 3);
else fustr_write_ch(ctx->out, ':');
fujson_fmt(aTHX_ ctx, UNLIKELY(SvMAGICAL(hv)) ? hv_iterval(hv, he) : HeVAL(he));
}
static void fujson_fmt_hv(pTHX_ fujson_fmt_ctx *ctx, HV *hv) {
HE *he;
char *hestr = NULL;
int numkeys = hv_iterinit(hv);
fustr_write_ch(ctx->out, '{');
ctx->pretty++;
/* Canonical order on tied hashes is not supported. Cpanel::JSON::XS has
* code to deal with that case and it's absolutely horrifying. */
if (ctx->canon && !(SvMAGICAL(hv) && SvTIED_mg((SV*)hv, PERL_MAGIC_tied))) {
SAVETMPS;
if (numkeys < 4) numkeys = 4;
if (SvMAGICAL(hv)) numkeys = 32;
SV *keys_sv = sv_2mortal(newSV(numkeys * sizeof(HE*)));
HE **keys = (HE **)SvPVX(keys_sv);
int i = 0;
while ((he = hv_iternext(hv))) {
if (i >= numkeys) {
numkeys += numkeys >> 1;
keys = (HE **)SvGROW(keys_sv, numkeys * sizeof(HE*));
numkeys = SvLEN(keys_sv) / sizeof(HE*);
}
keys[i++] = he;
}
qsort(keys, i, sizeof(HE *), fujson_fmt_hvcmp);
while (i--) fujson_fmt_hvkv(aTHX_ ctx, hv, keys[i], &hestr);
FREETMPS;
} else {
while ((he = hv_iternext(hv))) fujson_fmt_hvkv(aTHX_ ctx, hv, he, &hestr);
}
ctx->pretty--;
if (hestr) fujson_fmt_indent(aTHX_ ctx);
fustr_write_ch(ctx->out, '}');
}
static void fujson_fmt_obj(pTHX_ fujson_fmt_ctx *ctx, SV *rv, SV *obj) {
dSP;
GV *method = gv_fetchmethod_autoload(SvSTASH(obj), "TO_JSON", 0);
if (!method) croak("unable to format '%s' object as JSON", HvNAME(SvSTASH(obj)));
ENTER;
SAVETMPS;
PUSHMARK(SP);
XPUSHs(rv);
PUTBACK;
call_sv((SV *)GvCV(method), G_SCALAR);
SPAGAIN;
/* JSON::XS describes this error as "surprisingly common"... I'd be
* surprised indeed if it happens at all, but I suppose it can't hurt to
* copy their check; this sounds like be a pain to debug otherwise. */
if (SvROK(TOPs) && SvRV(TOPs) == obj)
croak("%s::TO_JSON method returned same object as was passed instead of a new one", HvNAME(SvSTASH(obj)));
obj = POPs;
PUTBACK;
fujson_fmt(aTHX_ ctx, obj);
FREETMPS;
LEAVE;
}
static void fujson_fmt(pTHX_ fujson_fmt_ctx *ctx, SV *val) {
SvGETMAGIC(val);
/* XXX: &PL_sv_yes and &PL_sv_no are proper booleans under 5.40, so no need
* to explicitly check for those; does this work in 5.36 as well? */
if (SvIsBOOL(val)) { /* Must check before IOKp & POKp, because bool implies both flags */
if (BOOL_INTERNALS_sv_isbool_true(val)) fustr_write(ctx->out, "true", 4);
else fustr_write(ctx->out, "false", 5);
} else if (SvPOKp(val)) {
fujson_fmt_str(aTHX_ ctx, SvPVX(val), SvCUR(val), SvUTF8(val));
} else if (SvNOKp(val)) { /* Must check before IOKp, because integer conversion might have been lossy */
NV nv = SvNV_nomg(val);
if (isinfnan(nv)) croak("unable to format floating point NaN or Inf as JSON");
/* XXX: Cpanel::JSON::XS appears to always append a ".0" for round numbers, other modules do not. */
/* XXX#2: This doesn't support quadmath. Makefile.PL checks for that */
fustr_reserve(ctx->out, NV_DIG+1);
Gconvert(nv, NV_DIG, 0, ctx->out->cur);
ctx->out->cur += strlen(ctx->out->cur);
} else if (SvIOKp(val)) {
fujson_fmt_int(aTHX_ ctx, val);
} else if (SvROK(val)) {
/* Simply consider every reference a form of nesting. TO_JSON may
* return a scalar, but it may also return another TO_JSON object and
* cause a stack overflow that way. */
if (--ctx->depth == 0) croak("max_depth exceeded while formatting JSON");
SV *rv = SvRV(val);
SvGETMAGIC(rv);
if (UNLIKELY(SvOBJECT(rv))) fujson_fmt_obj(aTHX_ ctx, val, rv);
else if (SvTYPE(rv) == SVt_PVHV) fujson_fmt_hv(aTHX_ ctx, (HV *)rv);
else if (SvTYPE(rv) == SVt_PVAV) fujson_fmt_av(aTHX_ ctx, (AV *)rv);
else croak("unable to format reference '%s' as JSON", SvPV_nolen(val));
ctx->depth++;
} else if (!SvOK(val)) {
fustr_write(ctx->out, "null", 4);
} else {
croak("unable to format unknown value '%s' as JSON", SvPV_nolen(val));
}
}
static SV *fujson_fmt_xs(pTHX_ I32 ax, I32 argc, SV *val) {
I32 i = 1;
int encutf8 = 0;
char *arg;
SV *r;
fustr out;
fujson_fmt_ctx ctx;
out.maxlen = 0;
ctx.out = &out;
ctx.depth = 0;
ctx.pretty = INT_MIN;
ctx.canon = 0;
while (i < argc) {
arg = SvPV_nolen(ST(i));
i++;
if (i == argc) croak("Odd name/value argument for json_format()");
r = ST(i);
i++;
if (strcmp(arg, "canonical") == 0) ctx.canon = SvPVXtrue(r);
else if (strcmp(arg, "pretty") == 0) ctx.pretty = SvPVXtrue(r) ? 0 : INT_MIN;
else if (strcmp(arg, "utf8") == 0) encutf8 = SvPVXtrue(r);
else if (strcmp(arg, "max_size") == 0) out.maxlen = SvUV(r);
else if (strcmp(arg, "max_depth") == 0) ctx.depth = SvUV(r);
else croak("Unknown flag: '%s'", arg);
}
if (out.maxlen == 0) out.maxlen = 1<<30;
if (ctx.depth == 0) ctx.depth = 512;
fustr_init(&out, sv_newmortal(), out.maxlen);
fujson_fmt(aTHX_ &ctx, val);
if (ctx.pretty >= 0) fustr_write_ch(&out, '\n');
r = fustr_done(&out);
if (!encutf8) SvUTF8_on(r);
return r;
}
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