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Commiteee6f9d

Browse files
committed
Rewrite nodeRead() in a less obfuscated fashion, per discussion with
Neil Conway.
1 parent839be02 commiteee6f9d

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4 files changed

+56
-84
lines changed

4 files changed

+56
-84
lines changed

‎src/backend/nodes/outfuncs.c

Lines changed: 1 addition & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -8,7 +8,7 @@
88
*
99
*
1010
* IDENTIFICATION
11-
* $PostgreSQL: pgsql/src/backend/nodes/outfuncs.c,v 1.233 2004/03/17 20:48:42 tgl Exp $
11+
* $PostgreSQL: pgsql/src/backend/nodes/outfuncs.c,v 1.234 2004/05/06 14:01:33 tgl Exp $
1212
*
1313
* NOTES
1414
* Every node type that can appear in stored rules' parsetrees *must*
@@ -130,7 +130,6 @@ _outToken(StringInfo str, char *s)
130130
/* These characters only need to be quoted at the start of the string */
131131
if (*s=='<'||
132132
*s=='\"'||
133-
*s=='@'||
134133
isdigit((unsignedchar)*s)||
135134
((*s=='+'||*s=='-')&&
136135
(isdigit((unsignedchar)s[1])||s[1]=='.')))

‎src/backend/nodes/read.c

Lines changed: 49 additions & 76 deletions
Original file line numberDiff line numberDiff line change
@@ -9,7 +9,7 @@
99
*
1010
*
1111
* IDENTIFICATION
12-
* $PostgreSQL: pgsql/src/backend/nodes/read.c,v 1.39 2004/01/09 03:07:32 momjian Exp $
12+
* $PostgreSQL: pgsql/src/backend/nodes/read.c,v 1.40 2004/05/06 14:01:33 tgl Exp $
1313
*
1414
* HISTORY
1515
* AUTHORDATEMAJOR EVENT
@@ -20,7 +20,6 @@
2020
#include"postgres.h"
2121

2222
#include<ctype.h>
23-
#include<errno.h>
2423

2524
#include"nodes/pg_list.h"
2625
#include"nodes/readfuncs.h"
@@ -51,7 +50,7 @@ stringToNode(char *str)
5150

5251
pg_strtok_ptr=str;/* point pg_strtok at the string to read */
5352

54-
retval=nodeRead(true);/* do the reading */
53+
retval=nodeRead(NULL,0);/* do the reading */
5554

5655
pg_strtok_ptr=save_strtok;
5756

@@ -184,17 +183,16 @@ debackslash(char *token, int length)
184183

185184
#defineRIGHT_PAREN (1000000 + 1)
186185
#defineLEFT_PAREN(1000000 + 2)
187-
#defineNODE_SYM(1000000 + 3)
188-
#defineAT_SYMBOL(1000000 + 4)
189-
#defineATOM_TOKEN(1000000 + 5)
186+
#defineLEFT_BRACE(1000000 + 3)
187+
#defineOTHER_TOKEN(1000000 + 4)
190188

191189
/*
192190
* nodeTokenType -
193191
* returns the type of the node token contained in token.
194192
* It returns one of the following valid NodeTags:
195193
*T_Integer, T_Float, T_String, T_BitString
196194
* and some of its own:
197-
*RIGHT_PAREN, LEFT_PAREN,NODE_SYM, AT_SYMBOL, ATOM_TOKEN
195+
*RIGHT_PAREN, LEFT_PAREN,LEFT_BRACE, OTHER_TOKEN
198196
*
199197
* Assumption: the ascii representation is legal
200198
*/
@@ -245,15 +243,13 @@ nodeTokenType(char *token, int length)
245243
elseif (*token==')')
246244
retval=RIGHT_PAREN;
247245
elseif (*token=='{')
248-
retval=NODE_SYM;
249-
elseif (*token=='@'&&length==1)
250-
retval=AT_SYMBOL;
246+
retval=LEFT_BRACE;
251247
elseif (*token=='\"'&&length>1&&token[length-1]=='\"')
252248
retval=T_String;
253249
elseif (*token=='b')
254250
retval=T_BitString;
255251
else
256-
retval=ATOM_TOKEN;
252+
retval=OTHER_TOKEN;
257253
returnretval;
258254
}
259255

@@ -266,77 +262,70 @@ nodeTokenType(char *token, int length)
266262
** Value token nodes (integers, floats, or strings);
267263
** General nodes (via parseNodeString() from readfuncs.c);
268264
** Lists of the above.
265+
* The return value is declared void *, not Node *, to avoid having to
266+
* cast it explicitly in callers that assign to fields of different types.
267+
*
268+
* External callers should always pass NULL/0 for the arguments. Internally
269+
* a non-NULL token may be passed when the upper recursion level has already
270+
* scanned the first token of a node's representation.
269271
*
270272
* We assume pg_strtok is already initialized with a string to read (hence
271273
* this should only be invoked from within a stringToNode operation).
272-
* Any callers should set read_car_only to true.
273274
*/
274275
void*
275-
nodeRead(boolread_car_only)
276+
nodeRead(char*token,inttok_len)
276277
{
277-
char*token;
278-
inttok_len;
278+
Node*result;
279279
NodeTagtype;
280-
Node*this_value,
281-
*return_value;
282-
boolmake_dotted_pair_cell= false;
283280

284-
token=pg_strtok(&tok_len);
281+
if (token==NULL)/* need to read a token? */
282+
{
283+
token=pg_strtok(&tok_len);
285284

286-
if (token==NULL)
287-
returnNULL;
285+
if (token==NULL)/* end of input */
286+
returnNULL;
287+
}
288288

289289
type=nodeTokenType(token,tok_len);
290290

291291
switch (type)
292292
{
293-
caseNODE_SYM:
294-
this_value=parseNodeString();
293+
caseLEFT_BRACE:
294+
result=parseNodeString();
295295
token=pg_strtok(&tok_len);
296296
if (token==NULL||token[0]!='}')
297297
elog(ERROR,"did not find '}' at end of input node");
298-
if (!read_car_only)
299-
make_dotted_pair_cell= true;
300-
else
301-
make_dotted_pair_cell= false;
302298
break;
303299
caseLEFT_PAREN:
304-
if (!read_car_only)
305300
{
306-
List*l=makeNode(List);
307-
308-
lfirst(l)=nodeRead(false);
309-
lnext(l)=nodeRead(false);
310-
this_value= (Node*)l;
301+
List*l=NIL;
302+
303+
for (;;)
304+
{
305+
token=pg_strtok(&tok_len);
306+
if (token==NULL)
307+
elog(ERROR,"unterminated List structure");
308+
if (token[0]==')')
309+
break;
310+
l=lappend(l,nodeRead(token,tok_len));
311+
}
312+
result= (Node*)l;
313+
break;
311314
}
312-
else
313-
this_value=nodeRead(false);
314-
break;
315315
caseRIGHT_PAREN:
316-
this_value=NULL;
317-
break;
318-
caseAT_SYMBOL:
319-
this_value=NULL;
316+
elog(ERROR,"unexpected right parenthesis");
317+
result=NULL;/* keep compiler happy */
320318
break;
321-
caseATOM_TOKEN:
319+
caseOTHER_TOKEN:
322320
if (tok_len==0)
323321
{
324-
/* must be "<>" */
325-
this_value=NULL;
326-
327-
/*
328-
* It might be NULL but it is an atom!
329-
*/
330-
if (read_car_only)
331-
make_dotted_pair_cell= false;
332-
else
333-
make_dotted_pair_cell= true;
322+
/* must be "<>" --- represents a null pointer */
323+
result=NULL;
334324
}
335325
else
336326
{
337-
/* !attention! result is not a Node. Use with caution. */
338-
this_value= (Node*)debackslash(token,tok_len);
339-
make_dotted_pair_cell= true;
327+
elog(ERROR,"unrecognized token: \"%.*s\"",tok_len,token);
328+
result=NULL;/* keep compiler happy */
340329
}
341330
break;
342331
caseT_Integer:
@@ -345,23 +334,20 @@ nodeRead(bool read_car_only)
345334
* we know that the token terminates on a char atol will stop
346335
* at
347336
*/
348-
this_value= (Node*)makeInteger(atol(token));
349-
make_dotted_pair_cell= true;
337+
result= (Node*)makeInteger(atol(token));
350338
break;
351339
caseT_Float:
352340
{
353341
char*fval= (char*)palloc(tok_len+1);
354342

355343
memcpy(fval,token,tok_len);
356344
fval[tok_len]='\0';
357-
this_value= (Node*)makeFloat(fval);
358-
make_dotted_pair_cell= true;
345+
result= (Node*)makeFloat(fval);
359346
}
360347
break;
361348
caseT_String:
362349
/* need to remove leading and trailing quotes, and backslashes */
363-
this_value= (Node*)makeString(debackslash(token+1,tok_len-2));
364-
make_dotted_pair_cell= true;
350+
result= (Node*)makeString(debackslash(token+1,tok_len-2));
365351
break;
366352
caseT_BitString:
367353
{
@@ -370,27 +356,14 @@ nodeRead(bool read_car_only)
370356
/* skip leading 'b' */
371357
strncpy(val,token+1,tok_len-1);
372358
val[tok_len-1]='\0';
373-
this_value= (Node*)makeBitString(val);
359+
result= (Node*)makeBitString(val);
374360
break;
375361
}
376362
default:
377363
elog(ERROR,"unrecognized node type: %d", (int)type);
378-
this_value=NULL;/* keep compiler happy */
364+
result=NULL;/* keep compiler happy */
379365
break;
380366
}
381-
if (make_dotted_pair_cell)
382-
{
383-
List*l=makeNode(List);
384367

385-
lfirst(l)=this_value;
386-
387-
if (!read_car_only)
388-
lnext(l)=nodeRead(false);
389-
else
390-
lnext(l)=NULL;
391-
return_value= (Node*)l;
392-
}
393-
else
394-
return_value=this_value;
395-
returnreturn_value;
368+
return (void*)result;
396369
}

‎src/backend/nodes/readfuncs.c

Lines changed: 4 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -8,7 +8,7 @@
88
*
99
*
1010
* IDENTIFICATION
11-
* $PostgreSQL: pgsql/src/backend/nodes/readfuncs.c,v 1.166 2004/03/17 20:48:42 tgl Exp $
11+
* $PostgreSQL: pgsql/src/backend/nodes/readfuncs.c,v 1.167 2004/05/06 14:01:33 tgl Exp $
1212
*
1313
* NOTES
1414
* Path and Plan nodes do not have any readfuncs support, because we
@@ -99,17 +99,17 @@
9999
/* Read a Node field */
100100
#defineREAD_NODE_FIELD(fldname) \
101101
token = pg_strtok(&length);/* skip :fldname */ \
102-
local_node->fldname=nodeRead(true)
102+
local_node->fldname=nodeRead(NULL,0)
103103

104104
/* Read an integer-list field */
105105
#defineREAD_INTLIST_FIELD(fldname) \
106106
token = pg_strtok(&length);/* skip :fldname */ \
107-
local_node->fldname=toIntList(nodeRead(true))
107+
local_node->fldname=toIntList(nodeRead(NULL,0))
108108

109109
/* Read an OID-list field */
110110
#defineREAD_OIDLIST_FIELD(fldname) \
111111
token = pg_strtok(&length);/* skip :fldname */ \
112-
local_node->fldname=toOidList(nodeRead(true))
112+
local_node->fldname=toOidList(nodeRead(NULL,0))
113113

114114
/* Routine exit */
115115
#defineREAD_DONE() \

‎src/include/nodes/readfuncs.h

Lines changed: 2 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -7,7 +7,7 @@
77
* Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
88
* Portions Copyright (c) 1994, Regents of the University of California
99
*
10-
* $PostgreSQL: pgsql/src/include/nodes/readfuncs.h,v 1.18 2003/11/29 22:41:06 pgsql Exp $
10+
* $PostgreSQL: pgsql/src/include/nodes/readfuncs.h,v 1.19 2004/05/06 14:01:33 tgl Exp $
1111
*
1212
*-------------------------------------------------------------------------
1313
*/
@@ -21,7 +21,7 @@
2121
*/
2222
externchar*pg_strtok(int*length);
2323
externchar*debackslash(char*token,intlength);
24-
externvoid*nodeRead(boolread_car_only);
24+
externvoid*nodeRead(char*token,inttok_len);
2525

2626
/*
2727
* prototypes for functions in readfuncs.c

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