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transmission/libtransmission/variant-json.c

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/*
* This file Copyright (C) Mnemosyne LLC
*
* This file is licensed by the GPL version 2. Works owned by the
* Transmission project are granted a special exemption to clause 2 (b)
* so that the bulk of its code can remain under the MIT license.
* This exemption does not extend to derived works not owned by
* the Transmission project.
*
* $Id$
*/
#include <assert.h>
#include <ctype.h>
#include <math.h> /* fabs() */
#include <stdio.h>
#include <string.h>
#include <errno.h> /* EILSEQ, EINVAL */
#include <locale.h> /* setlocale() */
#include <event2/buffer.h> /* evbuffer_add() */
#include <event2/util.h> /* evutil_strtoll () */
#define JSONSL_STATE_USER_FIELDS /* no fields */
#include "jsonsl.h"
#include "jsonsl.c"
#define __LIBTRANSMISSION_VARIANT_MODULE___
#include "transmission.h"
#include "ConvertUTF.h"
#include "list.h"
#include "ptrarray.h"
#include "utils.h"
#include "variant.h"
#include "variant-common.h"
/* arbitrary value... this is much deeper than our code goes */
#define MAX_DEPTH 64
struct json_wrapper_data
{
int error;
bool has_content;
tr_variant * top;
const char * key;
size_t keylen;
struct evbuffer * keybuf;
struct evbuffer * strbuf;
const char * source;
tr_ptrArray stack;
};
static tr_variant*
get_node (struct jsonsl_st * jsn)
{
tr_variant * parent;
tr_variant * node = NULL;
struct json_wrapper_data * data = jsn->data;
parent = tr_ptrArrayEmpty (&data->stack)
? NULL
: tr_ptrArrayBack (&data->stack);
if (!parent)
{
node = data->top;
}
else if (tr_variantIsList (parent))
{
node = tr_variantListAdd (parent);
}
else if (tr_variantIsDict (parent) && (data->key!=NULL))
{
node = tr_variantDictAdd (parent, data->key, data->keylen);
data->key = NULL;
data->keylen = 0;
}
return node;
}
static void
error_handler (jsonsl_t jsn,
jsonsl_error_t error,
struct jsonsl_state_st * state UNUSED,
const jsonsl_char_t * buf)
{
struct json_wrapper_data * data = jsn->data;
if (data->source)
{
tr_err ("JSON parse failed in %s at pos %zu: %s -- remaining text \"%.16s\"",
data->source,
jsn->pos,
jsonsl_strerror (error),
buf);
}
else
{
tr_err ("JSON parse failed at pos %zu: %s -- remaining text \"%.16s\"",
jsn->pos,
jsonsl_strerror (error),
buf);
}
data->error = EILSEQ;
}
static int
error_callback (jsonsl_t jsn,
jsonsl_error_t error,
struct jsonsl_state_st * state,
jsonsl_char_t * at)
{
error_handler (jsn, error, state, at);
return 0; /* bail */
}
static void
action_callback_PUSH (jsonsl_t jsn,
jsonsl_action_t action UNUSED,
struct jsonsl_state_st * state,
const jsonsl_char_t * buf UNUSED)
{
tr_variant * node;
struct json_wrapper_data * data = jsn->data;
switch (state->type)
{
case JSONSL_T_LIST:
data->has_content = true;
node = get_node (jsn);
tr_variantInitList (node, 0);
tr_ptrArrayAppend (&data->stack, node);
break;
case JSONSL_T_OBJECT:
data->has_content = true;
node = get_node (jsn);
tr_variantInitDict (node, 0);
tr_ptrArrayAppend (&data->stack, node);
break;
default:
/* nothing else interesting on push */
break;
}
}
/* like sscanf(in+2, "%4x", &val) but less slow */
static bool
decode_hex_string (const char * in, unsigned int * setme)
{
bool success;
char buf[5];
char * end;
assert (in != NULL);
assert (in[0] == '\\');
assert (in[1] == 'u');
memcpy (buf, in+2, 4);
buf[4] = '\0';
*setme = strtoul (buf, &end, 16);
success = end == buf+4;
return success;
}
static char*
extract_escaped_string (const char * in,
size_t in_len,
size_t * len,
struct evbuffer * buf)
{
const char * const in_end = in + in_len;
evbuffer_drain (buf, evbuffer_get_length (buf));
while (in < in_end)
{
bool unescaped = false;
if (*in=='\\' && in_end-in>=2)
{
switch (in[1])
{
case 'b' : evbuffer_add (buf, "\b", 1); in+=2; unescaped = true; break;
case 'f' : evbuffer_add (buf, "\f", 1); in+=2; unescaped = true; break;
case 'n' : evbuffer_add (buf, "\n", 1); in+=2; unescaped = true; break;
case 'r' : evbuffer_add (buf, "\r", 1); in+=2; unescaped = true; break;
case 't' : evbuffer_add (buf, "\t", 1); in+=2; unescaped = true; break;
case '/' : evbuffer_add (buf, "/" , 1); in+=2; unescaped = true; break;
case '"' : evbuffer_add (buf, "\"" , 1); in+=2; unescaped = true; break;
case '\\': evbuffer_add (buf, "\\", 1); in+=2; unescaped = true; break;
case 'u':
{
if (in_end - in >= 6)
{
unsigned int val = 0;
if (decode_hex_string (in, &val))
{
UTF32 str32_buf[2] = { val, 0 };
const UTF32 * str32_walk = str32_buf;
const UTF32 * str32_end = str32_buf + 1;
UTF8 str8_buf[8] = { 0, 0, 0, 0, 0, 0, 0, 0 };
UTF8 * str8_walk = str8_buf;
UTF8 * str8_end = str8_buf + 8;
if (ConvertUTF32toUTF8 (&str32_walk, str32_end, &str8_walk, str8_end, 0) == 0)
{
const size_t len = str8_walk - str8_buf;
evbuffer_add (buf, str8_buf, len);
unescaped = true;
}
in += 6;
break;
}
}
}
}
}
if (!unescaped)
{
evbuffer_add (buf, in, 1);
++in;
}
}
*len = evbuffer_get_length (buf);
return (char*) evbuffer_pullup (buf, -1);
}
static const char *
extract_string (jsonsl_t jsn,
struct jsonsl_state_st * state,
size_t * len,
struct evbuffer * buf)
{
const char * ret;
const char * in_begin;
const char * in_end;
size_t in_len;
/* figure out where the string is */
in_begin = jsn->base + state->pos_begin;
if (*in_begin == '"')
in_begin++;
in_end = jsn->base + state->pos_cur;
in_len = in_end - in_begin;
if (memchr (in_begin, '\\', in_len) == NULL)
{
/* it's not escaped */
ret = in_begin;
*len = in_len;
}
else
{
ret = extract_escaped_string (in_begin, in_len, len, buf);
}
return ret;
}
static void
action_callback_POP (jsonsl_t jsn,
jsonsl_action_t action UNUSED,
struct jsonsl_state_st * state,
const jsonsl_char_t * buf UNUSED)
{
struct json_wrapper_data * data = jsn->data;
if (state->type == JSONSL_T_STRING)
{
size_t len;
const char * str = extract_string (jsn, state, &len, data->strbuf);
tr_variantInitStr (get_node (jsn), str, len);
data->has_content = true;
}
else if (state->type == JSONSL_T_HKEY)
{
data->has_content = true;
data->key = extract_string (jsn, state, &data->keylen, data->keybuf);
}
else if ((state->type == JSONSL_T_LIST) || (state->type == JSONSL_T_OBJECT))
{
tr_ptrArrayPop (&data->stack);
}
else if (state->type == JSONSL_T_SPECIAL)
{
if (state->special_flags & JSONSL_SPECIALf_NUMNOINT)
{
const char * begin = jsn->base + state->pos_begin;
data->has_content = true;
tr_variantInitReal (get_node (jsn), strtod (begin, NULL));
}
else if (state->special_flags & JSONSL_SPECIALf_NUMERIC)
{
const char * begin = jsn->base + state->pos_begin;
data->has_content = true;
tr_variantInitInt (get_node (jsn), evutil_strtoll (begin, NULL, 10));
}
else if (state->special_flags & JSONSL_SPECIALf_BOOLEAN)
{
const bool b = (state->special_flags & JSONSL_SPECIALf_TRUE) != 0;
data->has_content = true;
tr_variantInitBool (get_node (jsn), b);
}
else if (state->special_flags & JSONSL_SPECIALf_NULL)
{
data->has_content = true;
tr_variantInitStr (get_node (jsn), "", 0);
}
}
}
int
tr_jsonParse (const char * source,
const void * vbuf,
size_t len,
tr_variant * setme_variant,
const char ** setme_end)
{
int error;
jsonsl_t jsn;
struct json_wrapper_data data;
jsn = jsonsl_new (MAX_DEPTH);
jsn->action_callback_PUSH = action_callback_PUSH;
jsn->action_callback_POP = action_callback_POP;
jsn->error_callback = error_callback;
jsn->data = &data;
jsonsl_enable_all_callbacks (jsn);
data.error = 0;
data.has_content = false;
data.key = NULL;
data.top = setme_variant;
data.stack = TR_PTR_ARRAY_INIT;
data.source = source;
data.keybuf = evbuffer_new ();
data.strbuf = evbuffer_new ();
/* parse it */
jsonsl_feed (jsn, vbuf, len);
/* EINVAL if there was no content */
if (!data.error && !data.has_content)
data.error = EINVAL;
/* maybe set the end ptr */
if (setme_end)
*setme_end = ((const char*)vbuf) + jsn->pos;
/* cleanup */
error = data.error;
evbuffer_free (data.keybuf);
evbuffer_free (data.strbuf);
tr_ptrArrayDestruct (&data.stack, NULL);
jsonsl_destroy (jsn);
return error;
}
/****
*****
****/
struct ParentState
{
int variantType;
int childIndex;
int childCount;
};
struct jsonWalk
{
bool doIndent;
tr_list * parents;
struct evbuffer * out;
};
static void
jsonIndent (struct jsonWalk * data)
{
if (data->doIndent)
{
char buf[1024];
const int width = tr_list_size (data->parents) * 4;
buf[0] = '\n';
memset (buf+1, ' ', width);
evbuffer_add (data->out, buf, 1+width);
}
}
static void
jsonChildFunc (struct jsonWalk * data)
{
if (data->parents && data->parents->data)
{
struct ParentState * pstate = data->parents->data;
switch (pstate->variantType)
{
case TR_VARIANT_TYPE_DICT:
{
const int i = pstate->childIndex++;
if (! (i % 2))
{
evbuffer_add (data->out, ": ", data->doIndent ? 2 : 1);
}
else
{
const bool isLast = pstate->childIndex == pstate->childCount;
if (!isLast)
{
evbuffer_add (data->out, ", ", data->doIndent ? 2 : 1);
jsonIndent (data);
}
}
break;
}
case TR_VARIANT_TYPE_LIST:
{
const bool isLast = ++pstate->childIndex == pstate->childCount;
if (!isLast)
{
evbuffer_add (data->out, ", ", data->doIndent ? 2 : 1);
jsonIndent (data);
}
break;
}
default:
break;
}
}
}
static void
jsonPushParent (struct jsonWalk * data,
const tr_variant * v)
{
struct ParentState * pstate = tr_new (struct ParentState, 1);
pstate->variantType = v->type;
pstate->childIndex = 0;
pstate->childCount = v->val.l.count;
tr_list_prepend (&data->parents, pstate);
}
static void
jsonPopParent (struct jsonWalk * data)
{
tr_free (tr_list_pop_front (&data->parents));
}
static void
jsonIntFunc (const tr_variant * val, void * vdata)
{
struct jsonWalk * data = vdata;
evbuffer_add_printf (data->out, "%" PRId64, val->val.i);
jsonChildFunc (data);
}
static void
jsonBoolFunc (const tr_variant * val,
void * vdata)
{
struct jsonWalk * data = vdata;
if (val->val.b)
evbuffer_add (data->out, "true", 4);
else
evbuffer_add (data->out, "false", 5);
jsonChildFunc (data);
}
static void
jsonRealFunc (const tr_variant * val,
void * vdata)
{
struct jsonWalk * data = vdata;
if (fabs (val->val.d - (int)val->val.d) < 0.00001)
evbuffer_add_printf (data->out, "%d", (int)val->val.d);
else
evbuffer_add_printf (data->out, "%.4f", tr_truncd (val->val.d, 4));
jsonChildFunc (data);
}
static void
jsonStringFunc (const tr_variant * val,
void * vdata)
{
char * out;
char * outwalk;
char * outend;
struct evbuffer_iovec vec[1];
struct jsonWalk * data = vdata;
const char * str;
size_t len;
const unsigned char * it;
const unsigned char * end;
tr_variantGetStr (val, &str, &len);
it = (const unsigned char *) str;
end = it + len;
evbuffer_reserve_space (data->out, len * 4, vec, 1);
out = vec[0].iov_base;
outend = out + vec[0].iov_len;
outwalk = out;
*outwalk++ = '"';
for (; it!=end; ++it)
{
switch (*it)
{
case '\b': *outwalk++ = '\\'; *outwalk++ = 'b'; break;
case '\f': *outwalk++ = '\\'; *outwalk++ = 'f'; break;
case '\n': *outwalk++ = '\\'; *outwalk++ = 'n'; break;
case '\r': *outwalk++ = '\\'; *outwalk++ = 'r'; break;
case '\t': *outwalk++ = '\\'; *outwalk++ = 't'; break;
case '"' : *outwalk++ = '\\'; *outwalk++ = '"'; break;
case '\\': *outwalk++ = '\\'; *outwalk++ = '\\'; break;
default:
if (isascii (*it))
{
*outwalk++ = *it;
}
else
{
const UTF8 * tmp = it;
UTF32 buf[1] = { 0 };
UTF32 * u32 = buf;
ConversionResult result = ConvertUTF8toUTF32 (&tmp, end, &u32, buf + 1, 0);
if (((result==conversionOK) || (result==targetExhausted)) && (tmp!=it))
{
outwalk += tr_snprintf (outwalk, outend-outwalk, "\\u%04x", (unsigned int)buf[0]);
it = tmp - 1;
}
}
break;
}
}
*outwalk++ = '"';
vec[0].iov_len = outwalk - out;
evbuffer_commit_space (data->out, vec, 1);
jsonChildFunc (data);
}
static void
jsonDictBeginFunc (const tr_variant * val,
void * vdata)
{
struct jsonWalk * data = vdata;
jsonPushParent (data, val);
evbuffer_add (data->out, "{", 1);
if (val->val.l.count)
jsonIndent (data);
}
static void
jsonListBeginFunc (const tr_variant * val,
void * vdata)
{
const size_t nChildren = tr_variantListSize (val);
struct jsonWalk * data = vdata;
jsonPushParent (data, val);
evbuffer_add (data->out, "[", 1);
if (nChildren)
jsonIndent (data);
}
static void
jsonContainerEndFunc (const tr_variant * val,
void * vdata)
{
struct jsonWalk * data = vdata;
int emptyContainer = false;
jsonPopParent (data);
if (!emptyContainer)
jsonIndent (data);
if (tr_variantIsDict (val))
evbuffer_add (data->out, "}", 1);
else /* list */
evbuffer_add (data->out, "]", 1);
jsonChildFunc (data);
}
static const struct VariantWalkFuncs walk_funcs = { jsonIntFunc,
jsonBoolFunc,
jsonRealFunc,
jsonStringFunc,
jsonDictBeginFunc,
jsonListBeginFunc,
jsonContainerEndFunc };
void
tr_variantToBufJson (const tr_variant * top, struct evbuffer * buf, bool lean)
{
char lc_numeric[128];
struct jsonWalk data;
data.doIndent = !lean;
data.out = buf;
data.parents = NULL;
/* json requires a '.' decimal point regardless of locale */
tr_strlcpy (lc_numeric, setlocale (LC_NUMERIC, NULL), sizeof (lc_numeric));
setlocale (LC_NUMERIC, "POSIX");
tr_variantWalk (top, &walk_funcs, &data, true);
setlocale (LC_NUMERIC, lc_numeric);
if (evbuffer_get_length (buf))
evbuffer_add_printf (buf, "\n");
}
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