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MXS-2302: Remove unused parsing code

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Removed all code that is no longer used. The hint stack mechanism is still
in use but can, and should, be replaced with std::vector.
This commit is contained in:
Markus Mäkelä
2019-02-17 21:21:38 +02:00
parent c5a8b693c3
commit ec234124b1
1 changed files with 4 additions and 636 deletions
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640
server/modules/filter/hintfilter/hintparser.cc
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@ -13,649 +13,17 @@
#define MXS_MODULE_NAME "hintfilter"
#include <stdio.h>
#include <ctype.h>
#include <string.h>
#include <unordered_map>
#include <maxscale/filter.hh>
#include <maxscale/modinfo.h>
#include <maxscale/modutil.hh>
#include <maxscale/buffer.hh>
#include "mysqlhint.hh"
#include <maxscale/alloc.h>
/**
* hintparser.c - Find any comment in the SQL packet and look for MAXSCALE
* hints in that comment.
* Code for parsing SQL comments and processing them into MaxScale hints
*/
/**
* The keywords in the hint syntax
*/
static struct
{
const char* keyword;
TOKEN_VALUE token;
} keywords[] =
{
{"maxscale", TOK_MAXSCALE },
{"prepare", TOK_PREPARE },
{"start", TOK_START },
{"begin", TOK_START },
{"stop", TOK_STOP },
{"end", TOK_STOP },
{"=", TOK_EQUAL },
{"route", TOK_ROUTE },
{"to", TOK_TO },
{"master", TOK_MASTER },
{"slave", TOK_SLAVE },
{"server", TOK_SERVER },
{"last", TOK_LAST },
{NULL, static_cast<TOKEN_VALUE>(0)}
};
static HINT_TOKEN* hint_next_token(GWBUF** buf, char** ptr);
static void hint_pop(HINT_SESSION*);
static HINT* lookup_named_hint(HINT_SESSION*, const char*);
static void create_named_hint(HINT_SESSION*, const char*, HINT*);
static void hint_push(HINT_SESSION*, HINT*);
static const char* token_get_keyword(HINT_TOKEN* token);
static void token_free(HINT_TOKEN* token);
typedef enum
{
HM_EXECUTE,
HM_START,
HM_PREPARE
} HINT_MODE;
void token_free(HINT_TOKEN* token)
{
if (token->value != NULL)
{
MXS_FREE(token->value);
}
MXS_FREE(token);
}
static const char* token_get_keyword(HINT_TOKEN* token)
{
switch (token->token)
{
case TOK_END:
return "End of hint";
break;
case TOK_LINEBRK:
return "End of line";
break;
case TOK_STRING:
return token->value;
break;
default:
{
int i = 0;
while (i < TOK_LINEBRK && keywords[i].token != token->token)
{
i++;
}
mxb_assert(i != TOK_LINEBRK);
if (i == TOK_LINEBRK)
{
return "Unknown token";
}
else
{
return keywords[i].keyword;
}
}
break;
}
}
/**
* Parse the hint comments in the MySQL statement passed in request.
* Add any hints to the buffer for later processing.
*
* @param session The filter session
* @param request The MySQL request buffer
* @return The hints parsed in this statement or active on the
* stack
*/
HINT* hint_parser(HINT_SESSION* session, GWBUF* request)
{
char* ptr, lastch = ' ';
int len, residual, state;
int found, escape, quoted, squoted;
HINT* rval = NULL;
char* pname = nullptr;
char* lvalue = nullptr;
char* hintname = nullptr;
GWBUF* buf;
HINT_TOKEN* tok;
HINT_MODE mode = HM_EXECUTE;
bool multiline_comment = false;
/* First look for any comment in the SQL */
modutil_MySQL_Query(request, &ptr, &len, &residual);
buf = request;
found = 0;
escape = 0;
quoted = 0;
squoted = 0;
do
{
while (len--)
{
if (*ptr == '\\')
{
escape = 1;
}
else if (*ptr == '\"' && quoted)
{
quoted = 0;
}
else if (*ptr == '\"' && quoted == 0)
{
quoted = 0;
}
else if (*ptr == '\'' && squoted)
{
squoted = 0;
}
else if (*ptr == '\"' && squoted == 0)
{
squoted = 0;
}
else if (quoted || squoted)
{
}
else if (escape)
{
escape = 0;
}
else if (*ptr == '#')
{
found = 1;
break;
}
else if (*ptr == '/')
{
lastch = '/';
}
else if (*ptr == '*' && lastch == '/')
{
found = 1;
multiline_comment = true;
break;
}
else if (*ptr == '-' && lastch == '-')
{
found = 1;
break;
}
else if (*ptr == '-')
{
lastch = '-';
}
else
{
lastch = *ptr;
}
ptr++;
}
if (found)
{
break;
}
buf = buf->next;
if (buf)
{
len = GWBUF_LENGTH(buf);
ptr = (char*)GWBUF_DATA(buf);
}
}
while (buf);
if (!found) /* No comment so we need do no more */
{
goto retblock;
}
/*
* If we have got here then we have a comment, ptr point to
* the comment character if it is a '#' comment or the second
* character of the comment if it is a -- or \/\* comment
*
* Move to the next character in the SQL.
*/
ptr++;
if (ptr > (char*)(buf->end))
{
buf = buf->next;
if (buf)
{
ptr = (char*)GWBUF_DATA(buf);
}
else
{
goto retblock;
}
}
tok = hint_next_token(&buf, &ptr);
if (tok == NULL)
{
goto retblock;
}
/** This is not MaxScale hint because it doesn't start with 'maxscale' */
if (tok->token != TOK_MAXSCALE)
{
token_free(tok);
goto retblock;
}
token_free(tok);
state = HS_INIT;
while (((tok = hint_next_token(&buf, &ptr)) != NULL)
&& (tok->token != TOK_END))
{
if (tok->token == TOK_LINEBRK)
{
if (multiline_comment)
{
// Skip token
token_free(tok);
continue;
}
else
{
// Treat as TOK_END
tok->token = TOK_END;
break;
}
}
switch (state)
{
case HS_INIT:
switch (tok->token)
{
case TOK_ROUTE:
state = HS_ROUTE;
break;
case TOK_STRING:
state = HS_NAME;
lvalue = MXS_STRDUP_A(tok->value);
break;
case TOK_STOP:
/* Action: pop active hint */
hint_pop(session);
state = HS_INIT;
break;
case TOK_START:
hintname = NULL;
mode = HM_START;
state = HS_INIT;
break;
default:
/* Error: expected hint, name or STOP */
MXS_ERROR("Syntax error in hint. Expected "
"'route', 'stop' or hint name instead of "
"'%s'. Hint ignored.",
token_get_keyword(tok));
token_free(tok);
goto retblock;
}
break;
case HS_ROUTE:
if (tok->token != TOK_TO)
{
/* Error, expect TO */
MXS_ERROR("Syntax error in hint. Expected "
"'to' instead of '%s'. Hint ignored.",
token_get_keyword(tok));
token_free(tok);
goto retblock;
}
state = HS_ROUTE1;
break;
case HS_ROUTE1:
switch (tok->token)
{
case TOK_MASTER:
rval = hint_create_route(rval,
HINT_ROUTE_TO_MASTER,
NULL);
break;
case TOK_SLAVE:
rval = hint_create_route(rval,
HINT_ROUTE_TO_SLAVE,
NULL);
break;
case TOK_LAST:
rval = hint_create_route(rval,
HINT_ROUTE_TO_LAST_USED,
NULL);
break;
case TOK_SERVER:
state = HS_ROUTE_SERVER;
break;
default:
/* Error expected MASTER, SLAVE or SERVER */
MXS_ERROR("Syntax error in hint. Expected "
"'master', 'slave', or 'server' instead "
"of '%s'. Hint ignored.",
token_get_keyword(tok));
token_free(tok);
goto retblock;
}
break;
case HS_ROUTE_SERVER:
if (tok->token == TOK_STRING)
{
rval = hint_create_route(rval,
HINT_ROUTE_TO_NAMED_SERVER,
tok->value);
}
else
{
/* Error: Expected server name */
MXS_ERROR("Syntax error in hint. Expected "
"server name instead of '%s'. Hint "
"ignored.",
token_get_keyword(tok));
token_free(tok);
goto retblock;
}
break;
case HS_NAME:
switch (tok->token)
{
case TOK_EQUAL:
pname = lvalue;
lvalue = NULL;
state = HS_PVALUE;
break;
case TOK_PREPARE:
pname = lvalue;
state = HS_PREPARE;
break;
case TOK_START:
/* Action start(lvalue) */
hintname = lvalue;
mode = HM_START;
state = HS_INIT;
break;
default:
/* Error, token tok->value not expected */
MXS_ERROR("Syntax error in hint. Expected "
"'=', 'prepare', or 'start' instead of "
"'%s'. Hint ignored.",
token_get_keyword(tok));
token_free(tok);
goto retblock;
}
break;
case HS_PVALUE:
/* Action: pname = tok->value */
rval = hint_create_parameter(rval, pname, tok->value);
MXS_FREE(pname);
pname = NULL;
state = HS_INIT;
break;
case HS_PREPARE:
mode = HM_PREPARE;
hintname = lvalue;
switch (tok->token)
{
case TOK_ROUTE:
state = HS_ROUTE;
break;
case TOK_STRING:
state = HS_NAME;
lvalue = tok->value;
break;
default:
/* Error, token tok->value not expected */
MXS_ERROR("Syntax error in hint. Expected "
"'route' or hint name instead of "
"'%s'. Hint ignored.",
token_get_keyword(tok));
token_free(tok);
goto retblock;
}
break;
}
token_free(tok);
} /*< while */
if (tok && tok->token == TOK_END)
{
token_free(tok);
}
switch (mode)
{
case HM_START:
/*
* We are starting either a predefined set of hints,
* creating a new set of hints and starting in a single
* operation or starting an anonymous block of hints.
*/
if (hintname == NULL && rval != NULL)
{
/* We are starting an anonymous block of hints */
hint_push(session, rval);
rval = NULL;
}
else if (hintname && rval)
{
/* We are creating and starting a block of hints */
if (lookup_named_hint(session, hintname) != NULL)
{
/* Error hint with this name already exists */
}
else
{
create_named_hint(session, hintname, rval);
hint_push(session, hint_dup(rval));
}
}
else if (hintname && rval == NULL)
{
/* We starting an already define set of named hints */
rval = lookup_named_hint(session, hintname);
hint_push(session, hint_dup(rval));
rval = NULL;
}
else if (hintname == NULL && rval == NULL)
{
/* Error case */
}
break;
case HM_PREPARE:
/*
* We are preparing a named set of hints. Note this does
* not trigger the usage of these hints currently.
*/
if (hintname == NULL || rval == NULL)
{
/* Error case, name and hints must be defined */
}
else
{
create_named_hint(session, hintname, rval);
}
/* We are not starting the hints now, so return an empty
* hint set.
*/
rval = NULL;
break;
case HM_EXECUTE:
/*
* We have a one-off hint for the statement we are
* currently forwarding.
*/
break;
}
retblock:
MXS_FREE(hintname);
if (rval == NULL)
{
/* No new hint parsed in this statement, apply the current
* top of stack if there is one.
*/
if (session->stack)
{
rval = hint_dup(session->stack->hint);
}
}
return rval;
}
/**
* Return the next token in the inout stream
*
* @param buf A pointer to the buffer point, will be updated if a
* new buffer is used.
* @param ptr The pointer within the buffer we are processing
* @return A HINT token
*/
static HINT_TOKEN* hint_next_token(GWBUF** buf, char** ptr)
{
char word[100], * dest;
int inword = 0;
int endtag = 0;
char inquote = '\0';
int i, found;
HINT_TOKEN* tok;
if ((tok = (HINT_TOKEN*)MXS_MALLOC(sizeof(HINT_TOKEN))) == NULL)
{
return NULL;
}
tok->value = NULL;
dest = word;
while (*ptr < (char*)((*buf)->end) || (*buf)->next)
{
/** word ends, don't move ptr but return with read word */
if (inword && inquote == '\0'
&& (isspace(**ptr) || **ptr == '='))
{
inword = 0;
break;
}
/** found '=' or '\n', move ptr and return with the char */
else if (!inword && inquote == '\0' && ((**ptr == '=') || (**ptr == '\n')))
{
*dest = **ptr;
dest++;
(*ptr)++;
break;
}
else if (**ptr == '\'' && inquote == '\'')
{
inquote = '\0';
}
else if (**ptr == '\'')
{
inquote = **ptr;
}
/** Any other character which belongs to the word, move ahead */
else if (**ptr == '/' && endtag)
{
/** Comment end tag found, rewind the pointer back and return the token */
inword = 0;
(*ptr)--;
break;
}
else if (**ptr == '*' && !endtag)
{
endtag = 1;
}
else if (inword || (isspace(**ptr) == 0))
{
*dest++ = **ptr;
inword = 1;
}
(*ptr)++;
if (*ptr > (char*)((*buf)->end) && (*buf)->next)
{
*buf = (*buf)->next;
*ptr = static_cast<char*>((*buf)->start);
}
if (dest - word > 98)
{
break;
}
} /*< while */
*dest = 0;
/* We now have a word in the local word, check to see if it is a
* token we recognise.
*/
if (word[0] == '\0' || (word[0] == '*' && word[1] == '/'))
{
tok->token = TOK_END;
return tok;
}
if (word[0] == '\n')
{
tok->token = TOK_LINEBRK;
return tok;
}
found = 0;
for (i = 0; keywords[i].keyword; i++)
{
if (strcasecmp(word, keywords[i].keyword) == 0)
{
tok->token = keywords[i].token;
found = 1;
break;
}
}
if (found == 0)
{
tok->token = TOK_STRING;
tok->value = MXS_STRDUP_A(word);
}
return tok;
}
/**
* hint_pop - pop the hint off the top of the stack if it is not empty
*