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Mypal/modules/libpref/prefread.cpp

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/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include "prefread.h"
#include "nsString.h"
#include "nsUTF8Utils.h"
#ifdef TEST_PREFREAD
#include <stdio.h>
#define NS_WARNING(_s) printf(">>> " _s "!\n")
#define NS_NOTREACHED(_s) NS_WARNING(_s)
#else
#include "nsDebug.h" // for NS_WARNING
#endif
/* pref parser states */
enum {
PREF_PARSE_INIT,
PREF_PARSE_MATCH_STRING,
PREF_PARSE_UNTIL_NAME,
PREF_PARSE_QUOTED_STRING,
PREF_PARSE_UNTIL_COMMA,
PREF_PARSE_UNTIL_VALUE,
PREF_PARSE_INT_VALUE,
PREF_PARSE_COMMENT_MAYBE_START,
PREF_PARSE_COMMENT_BLOCK,
PREF_PARSE_COMMENT_BLOCK_MAYBE_END,
PREF_PARSE_ESC_SEQUENCE,
PREF_PARSE_HEX_ESCAPE,
PREF_PARSE_UTF16_LOW_SURROGATE,
PREF_PARSE_UNTIL_OPEN_PAREN,
PREF_PARSE_UNTIL_CLOSE_PAREN,
PREF_PARSE_UNTIL_SEMICOLON,
PREF_PARSE_UNTIL_EOL
};
#define UTF16_ESC_NUM_DIGITS 4
#define HEX_ESC_NUM_DIGITS 2
#define BITS_PER_HEX_DIGIT 4
static const char kUserPref[] = "user_pref";
static const char kPref[] = "pref";
static const char kPrefSticky[] = "sticky_pref";
static const char kTrue[] = "true";
static const char kFalse[] = "false";
/**
* pref_GrowBuf
*
* this function will increase the size of the buffer owned
* by the given pref parse state. We currently use a simple
* doubling algorithm, but the only hard requirement is that
* it increase the buffer by at least the size of the ps->esctmp
* buffer used for escape processing (currently 6 bytes).
*
* this buffer is used to store partial pref lines. it is
* freed when the parse state is destroyed.
*
* @param ps
* parse state instance
*
* this function updates all pointers that reference an
* address within lb since realloc may relocate the buffer.
*
* @return false if insufficient memory.
*/
static bool
pref_GrowBuf(PrefParseState *ps)
{
int bufLen, curPos, valPos;
bufLen = ps->lbend - ps->lb;
curPos = ps->lbcur - ps->lb;
valPos = ps->vb - ps->lb;
if (bufLen == 0)
bufLen = 128; /* default buffer size */
else
bufLen <<= 1; /* double buffer size */
#ifdef TEST_PREFREAD
fprintf(stderr, ">>> realloc(%d)\n", bufLen);
#endif
ps->lb = (char*) realloc(ps->lb, bufLen);
if (!ps->lb)
return false;
ps->lbcur = ps->lb + curPos;
ps->lbend = ps->lb + bufLen;
ps->vb = ps->lb + valPos;
return true;
}
/**
* Report an error or a warning. If not specified, just dump to stderr.
*/
static void
pref_ReportParseProblem(PrefParseState& ps, const char* aMessage, int aLine, bool aError)
{
if (ps.reporter) {
ps.reporter(aMessage, aLine, aError);
} else {
printf_stderr("**** Preference parsing %s (line %d) = %s **\n",
(aError ? "error" : "warning"), aLine, aMessage);
}
}
/**
* pref_DoCallback
*
* this function is called when a complete pref name-value pair has
* been extracted from the input data.
*
* @param ps
* parse state instance
*
* @return false to indicate a fatal error.
*/
static bool
pref_DoCallback(PrefParseState *ps)
{
PrefValue value;
switch (ps->vtype) {
case PrefType::String:
value.stringVal = ps->vb;
break;
case PrefType::Int:
if ((ps->vb[0] == '-' || ps->vb[0] == '+') && ps->vb[1] == '\0') {
pref_ReportParseProblem(*ps, "invalid integer value", 0, true);
NS_WARNING("malformed integer value");
return false;
}
value.intVal = atoi(ps->vb);
break;
case PrefType::Bool:
value.boolVal = (ps->vb == kTrue);
break;
default:
break;
}
(*ps->reader)(ps->closure, ps->lb, value, ps->vtype, ps->fdefault,
ps->fstickydefault);
return true;
}
void
PREF_InitParseState(PrefParseState *ps, PrefReader reader,
PrefParseErrorReporter reporter, void *closure)
{
memset(ps, 0, sizeof(*ps));
ps->reader = reader;
ps->closure = closure;
ps->reporter = reporter;
}
void
PREF_FinalizeParseState(PrefParseState *ps)
{
if (ps->lb)
free(ps->lb);
}
/**
* Pseudo-BNF
* ----------
* function = LJUNK function-name JUNK function-args
* function-name = "user_pref" | "pref" | "sticky_pref"
* function-args = "(" JUNK pref-name JUNK "," JUNK pref-value JUNK ")" JUNK ";"
* pref-name = quoted-string
* pref-value = quoted-string | "true" | "false" | integer-value
* JUNK = *(WS | comment-block | comment-line)
* LJUNK = *(WS | comment-block | comment-line | bcomment-line)
* WS = SP | HT | LF | VT | FF | CR
* SP = <US-ASCII SP, space (32)>
* HT = <US-ASCII HT, horizontal-tab (9)>
* LF = <US-ASCII LF, linefeed (10)>
* VT = <US-ASCII HT, vertical-tab (11)>
* FF = <US-ASCII FF, form-feed (12)>
* CR = <US-ASCII CR, carriage return (13)>
* comment-block = <C/C++ style comment block>
* comment-line = <C++ style comment line>
* bcomment-line = <bourne-shell style comment line>
*/
bool
PREF_ParseBuf(PrefParseState *ps, const char *buf, int bufLen)
{
const char *end;
char c;
char udigit;
int state;
// The line number is currently only used for the error/warning reporting.
int lineNum = 0;
state = ps->state;
for (end = buf + bufLen; buf != end; ++buf) {
c = *buf;
if (c == '\r' || c == '\n' || c == 0x1A) {
lineNum ++;
}
switch (state) {
/* initial state */
case PREF_PARSE_INIT:
if (ps->lbcur != ps->lb) { /* reset state */
ps->lbcur = ps->lb;
ps->vb = nullptr;
ps->vtype = PrefType::Invalid;
ps->fdefault = false;
ps->fstickydefault = false;
}
switch (c) {
case '/': /* begin comment block or line? */
state = PREF_PARSE_COMMENT_MAYBE_START;
break;
case '#': /* accept shell style comments */
state = PREF_PARSE_UNTIL_EOL;
break;
case 'u': /* indicating user_pref */
case 's': /* indicating sticky_pref */
case 'p': /* indicating pref */
if (c == 'u') {
ps->smatch = kUserPref;
} else if (c == 's') {
ps->smatch = kPrefSticky;
} else {
ps->smatch = kPref;
}
ps->sindex = 1;
ps->nextstate = PREF_PARSE_UNTIL_OPEN_PAREN;
state = PREF_PARSE_MATCH_STRING;
break;
/* else skip char */
}
break;
/* string matching */
case PREF_PARSE_MATCH_STRING:
if (c == ps->smatch[ps->sindex++]) {
/* if we've matched all characters, then move to next state. */
if (ps->smatch[ps->sindex] == '\0') {
state = ps->nextstate;
ps->nextstate = PREF_PARSE_INIT; /* reset next state */
}
/* else wait for next char */
}
else {
pref_ReportParseProblem(*ps, "non-matching string", lineNum, true);
NS_WARNING("malformed pref file");
return false;
}
break;
/* quoted string parsing */
case PREF_PARSE_QUOTED_STRING:
/* we assume that the initial quote has already been consumed */
if (ps->lbcur == ps->lbend && !pref_GrowBuf(ps))
return false; /* out of memory */
if (c == '\\')
state = PREF_PARSE_ESC_SEQUENCE;
else if (c == ps->quotechar) {
*ps->lbcur++ = '\0';
state = ps->nextstate;
ps->nextstate = PREF_PARSE_INIT; /* reset next state */
}
else
*ps->lbcur++ = c;
break;
/* name parsing */
case PREF_PARSE_UNTIL_NAME:
if (c == '\"' || c == '\'') {
ps->fdefault = (ps->smatch == kPref || ps->smatch == kPrefSticky);
ps->fstickydefault = (ps->smatch == kPrefSticky);
ps->quotechar = c;
ps->nextstate = PREF_PARSE_UNTIL_COMMA; /* return here when done */
state = PREF_PARSE_QUOTED_STRING;
}
else if (c == '/') { /* allow embedded comment */
ps->nextstate = state; /* return here when done with comment */
state = PREF_PARSE_COMMENT_MAYBE_START;
}
else if (!isspace(c)) {
pref_ReportParseProblem(*ps, "need space, comment or quote", lineNum, true);
NS_WARNING("malformed pref file");
return false;
}
break;
/* parse until we find a comma separating name and value */
case PREF_PARSE_UNTIL_COMMA:
if (c == ',') {
ps->vb = ps->lbcur;
state = PREF_PARSE_UNTIL_VALUE;
}
else if (c == '/') { /* allow embedded comment */
ps->nextstate = state; /* return here when done with comment */
state = PREF_PARSE_COMMENT_MAYBE_START;
}
else if (!isspace(c)) {
pref_ReportParseProblem(*ps, "need space, comment or comma", lineNum, true);
NS_WARNING("malformed pref file");
return false;
}
break;
/* value parsing */
case PREF_PARSE_UNTIL_VALUE:
/* the pref value type is unknown. so, we scan for the first
* character of the value, and determine the type from that. */
if (c == '\"' || c == '\'') {
ps->vtype = PrefType::String;
ps->quotechar = c;
ps->nextstate = PREF_PARSE_UNTIL_CLOSE_PAREN;
state = PREF_PARSE_QUOTED_STRING;
}
else if (c == 't' || c == 'f') {
ps->vb = (char *) (c == 't' ? kTrue : kFalse);
ps->vtype = PrefType::Bool;
ps->smatch = ps->vb;
ps->sindex = 1;
ps->nextstate = PREF_PARSE_UNTIL_CLOSE_PAREN;
state = PREF_PARSE_MATCH_STRING;
}
else if (isdigit(c) || (c == '-') || (c == '+')) {
ps->vtype = PrefType::Int;
/* write c to line buffer... */
if (ps->lbcur == ps->lbend && !pref_GrowBuf(ps))
return false; /* out of memory */
*ps->lbcur++ = c;
state = PREF_PARSE_INT_VALUE;
}
else if (c == '/') { /* allow embedded comment */
ps->nextstate = state; /* return here when done with comment */
state = PREF_PARSE_COMMENT_MAYBE_START;
}
else if (!isspace(c)) {
pref_ReportParseProblem(*ps, "need value, comment or space", lineNum, true);
NS_WARNING("malformed pref file");
return false;
}
break;
case PREF_PARSE_INT_VALUE:
/* grow line buffer if necessary... */
if (ps->lbcur == ps->lbend && !pref_GrowBuf(ps))
return false; /* out of memory */
if (isdigit(c))
*ps->lbcur++ = c;
else {
*ps->lbcur++ = '\0'; /* stomp null terminator; we are done. */
if (c == ')')
state = PREF_PARSE_UNTIL_SEMICOLON;
else if (c == '/') { /* allow embedded comment */
ps->nextstate = PREF_PARSE_UNTIL_CLOSE_PAREN;
state = PREF_PARSE_COMMENT_MAYBE_START;
}
else if (isspace(c))
state = PREF_PARSE_UNTIL_CLOSE_PAREN;
else {
pref_ReportParseProblem(*ps, "while parsing integer", lineNum, true);
NS_WARNING("malformed pref file");
return false;
}
}
break;
/* comment parsing */
case PREF_PARSE_COMMENT_MAYBE_START:
switch (c) {
case '*': /* comment block */
state = PREF_PARSE_COMMENT_BLOCK;
break;
case '/': /* comment line */
state = PREF_PARSE_UNTIL_EOL;
break;
default:
/* pref file is malformed */
pref_ReportParseProblem(*ps, "while parsing comment", lineNum, true);
NS_WARNING("malformed pref file");
return false;
}
break;
case PREF_PARSE_COMMENT_BLOCK:
if (c == '*')
state = PREF_PARSE_COMMENT_BLOCK_MAYBE_END;
break;
case PREF_PARSE_COMMENT_BLOCK_MAYBE_END:
switch (c) {
case '/':
state = ps->nextstate;
ps->nextstate = PREF_PARSE_INIT;
break;
case '*': /* stay in this state */
break;
default:
state = PREF_PARSE_COMMENT_BLOCK;
}
break;
/* string escape sequence parsing */
case PREF_PARSE_ESC_SEQUENCE:
/* not necessary to resize buffer here since we should be writing
* only one character and the resize check would have been done
* for us in the previous state */
switch (c) {
case '\"':
case '\'':
case '\\':
break;
case 'r':
c = '\r';
break;
case 'n':
c = '\n';
break;
case 'x': /* hex escape -- always interpreted as Latin-1 */
case 'u': /* UTF16 escape */
ps->esctmp[0] = c;
ps->esclen = 1;
ps->utf16[0] = ps->utf16[1] = 0;
ps->sindex = (c == 'x' ) ?
HEX_ESC_NUM_DIGITS :
UTF16_ESC_NUM_DIGITS;
state = PREF_PARSE_HEX_ESCAPE;
continue;
default:
pref_ReportParseProblem(*ps, "preserving unexpected JS escape sequence",
lineNum, false);
NS_WARNING("preserving unexpected JS escape sequence");
/* Invalid escape sequence so we do have to write more than
* one character. Grow line buffer if necessary... */
if ((ps->lbcur+1) == ps->lbend && !pref_GrowBuf(ps))
return false; /* out of memory */
*ps->lbcur++ = '\\'; /* preserve the escape sequence */
break;
}
*ps->lbcur++ = c;
state = PREF_PARSE_QUOTED_STRING;
break;
/* parsing a hex (\xHH) or utf16 escape (\uHHHH) */
case PREF_PARSE_HEX_ESCAPE:
if ( c >= '0' && c <= '9' )
udigit = (c - '0');
else if ( c >= 'A' && c <= 'F' )
udigit = (c - 'A') + 10;
else if ( c >= 'a' && c <= 'f' )
udigit = (c - 'a') + 10;
else {
/* bad escape sequence found, write out broken escape as-is */
pref_ReportParseProblem(*ps, "preserving invalid or incomplete hex escape",
lineNum, false);
NS_WARNING("preserving invalid or incomplete hex escape");
*ps->lbcur++ = '\\'; /* original escape slash */
if ((ps->lbcur + ps->esclen) >= ps->lbend && !pref_GrowBuf(ps))
return false;
for (int i = 0; i < ps->esclen; ++i)
*ps->lbcur++ = ps->esctmp[i];
/* push the non-hex character back for re-parsing. */
/* (++buf at the top of the loop keeps this safe) */
--buf;
state = PREF_PARSE_QUOTED_STRING;
continue;
}
/* have a digit */
ps->esctmp[ps->esclen++] = c; /* preserve it */
ps->utf16[1] <<= BITS_PER_HEX_DIGIT;
ps->utf16[1] |= udigit;
ps->sindex--;
if (ps->sindex == 0) {
/* have the full escape. Convert to UTF8 */
int utf16len = 0;
if (ps->utf16[0]) {
/* already have a high surrogate, this is a two char seq */
utf16len = 2;
}
else if (0xD800 == (0xFC00 & ps->utf16[1])) {
/* a high surrogate, can't convert until we have the low */
ps->utf16[0] = ps->utf16[1];
ps->utf16[1] = 0;
state = PREF_PARSE_UTF16_LOW_SURROGATE;
break;
}
else {
/* a single utf16 character */
ps->utf16[0] = ps->utf16[1];
utf16len = 1;
}
/* actual conversion */
/* make sure there's room, 6 bytes is max utf8 len (in */
/* theory; 4 bytes covers the actual utf16 range) */
if (ps->lbcur+6 >= ps->lbend && !pref_GrowBuf(ps))
return false;
ConvertUTF16toUTF8 converter(ps->lbcur);
converter.write(ps->utf16, utf16len);
ps->lbcur += converter.Size();
state = PREF_PARSE_QUOTED_STRING;
}
break;
/* looking for beginning of utf16 low surrogate */
case PREF_PARSE_UTF16_LOW_SURROGATE:
if (ps->sindex == 0 && c == '\\') {
++ps->sindex;
}
else if (ps->sindex == 1 && c == 'u') {
/* escape sequence is correct, now parse hex */
ps->sindex = UTF16_ESC_NUM_DIGITS;
ps->esctmp[0] = 'u';
ps->esclen = 1;
state = PREF_PARSE_HEX_ESCAPE;
}
else {
/* didn't find expected low surrogate. Ignore high surrogate
* (it would just get converted to nothing anyway) and start
* over with this character */
--buf;
if (ps->sindex == 1)
state = PREF_PARSE_ESC_SEQUENCE;
else
state = PREF_PARSE_QUOTED_STRING;
continue;
}
break;
/* function open and close parsing */
case PREF_PARSE_UNTIL_OPEN_PAREN:
/* tolerate only whitespace and embedded comments */
if (c == '(')
state = PREF_PARSE_UNTIL_NAME;
else if (c == '/') {
ps->nextstate = state; /* return here when done with comment */
state = PREF_PARSE_COMMENT_MAYBE_START;
}
else if (!isspace(c)) {
pref_ReportParseProblem(*ps, "need space, comment or open parentheses",
lineNum, true);
NS_WARNING("malformed pref file");
return false;
}
break;
case PREF_PARSE_UNTIL_CLOSE_PAREN:
/* tolerate only whitespace and embedded comments */
if (c == ')') {
state = PREF_PARSE_UNTIL_SEMICOLON;
} else if (c == '/') {
ps->nextstate = state; /* return here when done with comment */
state = PREF_PARSE_COMMENT_MAYBE_START;
} else if (!isspace(c)) {
pref_ReportParseProblem(*ps, "need space, comment or closing parentheses",
lineNum, true);
NS_WARNING("malformed pref file");
return false;
}
break;
/* function terminator ';' parsing */
case PREF_PARSE_UNTIL_SEMICOLON:
/* tolerate only whitespace and embedded comments */
if (c == ';') {
if (!pref_DoCallback(ps))
return false;
state = PREF_PARSE_INIT;
}
else if (c == '/') {
ps->nextstate = state; /* return here when done with comment */
state = PREF_PARSE_COMMENT_MAYBE_START;
}
else if (!isspace(c)) {
pref_ReportParseProblem(*ps, "need space, comment or semicolon",
lineNum, true);
NS_WARNING("malformed pref file");
return false;
}
break;
/* eol parsing */
case PREF_PARSE_UNTIL_EOL:
/* need to handle mac, unix, or dos line endings.
* PREF_PARSE_INIT will eat the next \n in case
* we have \r\n. */
if (c == '\r' || c == '\n' || c == 0x1A) {
state = ps->nextstate;
ps->nextstate = PREF_PARSE_INIT; /* reset next state */
}
break;
}
}
ps->state = state;
return true;
}
#ifdef TEST_PREFREAD
static void
pref_reader(void *closure,
const char *pref,
PrefValue val,
PrefType type,
bool defPref)
{
printf("%spref(\"%s\", ", defPref ? "" : "user_", pref);
switch (type) {
case PREF_STRING:
printf("\"%s\");\n", val.stringVal);
break;
case PREF_INT:
printf("%i);\n", val.intVal);
break;
case PREF_BOOL:
printf("%s);\n", val.boolVal == false ? "false" : "true");
break;
}
}
int
main(int argc, char **argv)
{
PrefParseState ps;
char buf[4096]; /* i/o buffer */
FILE *fp;
int n;
if (argc == 1) {
printf("usage: prefread file.js\n");
return -1;
}
fp = fopen(argv[1], "r");
if (!fp) {
printf("failed to open file\n");
return -1;
}
PREF_InitParseState(&ps, pref_reader, nullptr, nullptr);
while ((n = fread(buf, 1, sizeof(buf), fp)) > 0)
PREF_ParseBuf(&ps, buf, n);
PREF_FinalizeParseState(&ps);
fclose(fp);
return 0;
}
#endif /* TEST_PREFREAD */
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