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script-token.c
1/*
2%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
3% %
4% %
5% SSS CCC RRRR III PPPP TTTTT TTTTT OOO K K EEEE N N %
6% S C R R I P P T T O O K K E NN N %
7% SSS C RRRR I PPPP T T O O KK EEE N N N %
8% S C R R I P T T O O K K E N NN %
9% SSSS CCC R RR III P T T OOO K K EEEE N N %
10% %
11% Tokenize Magick Script into Options %
12% %
13% Dragon Computing %
14% Anthony Thyssen %
15% January 2012 %
16% %
17% %
18% Copyright @ 2012 ImageMagick Studio LLC, a non-profit organization %
19% dedicated to making software imaging solutions freely available. %
20% %
21% You may not use this file except in compliance with the License. You may %
22% obtain a copy of the License at %
23% %
24% https://imagemagick.org/script/license.php %
25% %
26% Unless required by applicable law or agreed to in writing, software %
27% distributed under the License is distributed on an "AS IS" BASIS, %
28% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. %
29% See the License for the specific language governing permissions and %
30% limitations under the License. %
31% %
32%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
33%
34% Read a stream of characters and return tokens one at a time.
35%
36% The input stream is divided into individual 'tokens' (representing 'words'
37% or 'options'), in a way that is as close to a UNIX shell, as is feasible.
38% Only shell variable, and command substitutions will not be performed.
39% Tokens can be any length.
40%
41% The main function call is GetScriptToken() (see below) which returns one
42% and only one token at a time. The other functions provide support to this
43% function, opening scripts, and setting up the required structures.
44%
45% More specifically...
46%
47% Tokens are white space separated, and may be quoted, or even partially
48% quoted by either single or double quotes, or the use of backslashes,
49% or any mix of the three.
50%
51% For example: This\ is' a 'single" token"
52%
53% A token is returned immediately the end of token is found. That is as soon
54% as a unquoted white-space or EOF condition has been found. That is to say
55% the file stream is parsed purely character-by-character, regardless any
56% buffering constraints set by the system. It is not parsed line-by-line.
57%
58% The function will return 'MagickTrue' if a valid token was found, while
59% the token status will be set accordingly to 'OK' or 'EOF', according to
60% the cause of the end of token. The token may be an empty string if the
61% input was a quoted empty string. Other error conditions return a value of
62% MagickFalse, indicating any token found but was incomplete due to some
63% error condition.
64%
65% Single quotes will preserve all characters including backslashes. Double
66% quotes will also preserve backslashes unless escaping a double quote,
67% or another backslashes. Other shell meta-characters are not treated as
68% special by this tokenizer.
69%
70% For example Quoting the quote chars:
71% \' "'" \" '"' "\"" \\ '\' "\\"
72%
73% Outside quotes, backslash characters will make spaces, tabs and quotes part
74% of a token returned. However a backslash at the end of a line (and outside
75% quotes) will cause the newline to be completely ignored (as per the shell
76% line continuation).
77%
78% Comments start with a '#' character at the start of a new token, will be
79% completely ignored upto the end of line, regardless of any backslash at the
80% end of the line. You can escape a comment '#', using quotes or backslashes
81% just as you can in a shell.
82%
83% The parser will accept both newlines, returns, or return-newlines to mark
84% the EOL. Though this is technically breaking (or perhaps adding to) the
85% 'BASH' syntax that is being followed.
86%
87%
88% UNIX script Launcher...
89%
90% The use of '#' comments allow normal UNIX 'scripting' to be used to call on
91% the "magick" command to parse the tokens from a file
92%
93% #!/path/to/command/magick -script
94%
95%
96% UNIX 'env' command launcher...
97%
98% If "magick" is renamed "magick-script" you can use a 'env' UNIX launcher
99%
100% #!/usr/bin/env magick-script
101%
102%
103% Shell script launcher...
104%
105% As a special case a ':' at the start of a line is also treated as a comment
106% This allows a magick script to ignore a line that can be parsed by the shell
107% and not by the magick script (tokenizer). This allows for an alternative
108% script 'launcher' to be used for magick scripts.
109%
110% #!/bin/sh
111% :; exec magick -script "$0" "$@"; exit 10
112% #
113% # The rest of the file is magick script
114% -read label:"This is a Magick Script!"
115% -write show: -exit
116%
117% Or with some shell pre/post processing...
118%
119% #!/bin/sh
120% :; echo "This part is run in the shell, but ignored by Magick"
121% :; magick -script "$0" "$@"
122% :; echo "This is run after the "magick" script is finished!"
123% :; exit 10
124% #
125% # The rest of the file is magick script
126% -read label:"This is a Magick Script!"
127% -write show: -exit
128%
129%
130% DOS script launcher...
131%
132% Similarly any '@' at the start of the line (outside of quotes) will also be
133% treated as comment. This allow you to create a DOS script launcher, to
134% allow a ".bat" DOS scripts to run as "magick" scripts instead.
135%
136% @echo This line is DOS executed but ignored by Magick
137% @magick -script %~dpnx0 %*
138% @echo This line is processed after the Magick script is finished
139% @GOTO :EOF
140% #
141% # The rest of the file is magick script
142% -read label:"This is a Magick Script!"
143% -write show: -exit
144%
145% But this can also be used as a shell script launcher as well!
146% Though is more restrictive and less free-form than using ':'.
147%
148% #!/bin/sh
149% @() { exec magick -script "$@"; }
150% @ "$0" "$@"; exit
151% #
152% # The rest of the file is magick script
153% -read label:"This is a Magick Script!"
154% -write show: -exit
155%
156% Or even like this...
157%
158% #!/bin/sh
159% @() { }
160% @; exec magick -script "$0" "$@"; exit
161% #
162% # The rest of the file is magick script
163% -read label:"This is a Magick Script!"
164% -write show: -exit
165%
166*/
167
168/*
169 Include declarations.
170
171 NOTE: Do not include if being compiled into the "test/script-token-test.c"
172 module, for low level token testing.
173*/
174#ifndef SCRIPT_TOKEN_TESTING
175# include "MagickWand/studio.h"
176# include "MagickWand/MagickWand.h"
177# include "MagickWand/script-token.h"
178# include "MagickCore/string-private.h"
179# include "MagickCore/utility-private.h"
180#endif
181
182/*
183%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
184% %
185% %
186% %
187% A c q u i r e S c r i p t T o k e n I n f o %
188% %
189% %
190% %
191%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
192%
193% AcquireScriptTokenInfo() allocated, initializes and opens the given
194% file stream from which tokens are to be extracted.
195%
196% The format of the AcquireScriptTokenInfo method is:
197%
198% ScriptTokenInfo *AcquireScriptTokenInfo(char *filename)
199%
200% A description of each parameter follows:
201%
202% o filename the filename to open ("-" means stdin)
203%
204*/
205WandExport ScriptTokenInfo *AcquireScriptTokenInfo(const char *filename)
206{
208 *token_info;
209
210 token_info=(ScriptTokenInfo *) AcquireMagickMemory(sizeof(*token_info));
211 if (token_info == (ScriptTokenInfo *) NULL)
212 return token_info;
213 (void) memset(token_info,0,sizeof(*token_info));
214
215 token_info->opened=MagickFalse;
216 if ( LocaleCompare(filename,"-") == 0 ) {
217 token_info->stream=stdin;
218 token_info->opened=MagickFalse;
219 }
220 else if ( LocaleNCompare(filename,"fd:",3) == 0 ) {
221 token_info->stream=fdopen(StringToLong(filename+3),"r");
222 token_info->opened=MagickFalse;
223 }
224 else {
225 token_info->stream=fopen_utf8(filename, "r");
226 }
227 if ( token_info->stream == (FILE *) NULL ) {
228 token_info=(ScriptTokenInfo *) RelinquishMagickMemory(token_info);
229 return(token_info);
230 }
231
232 token_info->curr_line=1;
233 token_info->length=INITAL_TOKEN_LENGTH;
234 token_info->token=(char *) AcquireQuantumMemory(1,token_info->length);
235
236 token_info->status=(token_info->token != (char *) NULL)
237 ? TokenStatusOK : TokenStatusMemoryFailed;
238 token_info->signature=MagickWandSignature;
239
240 return token_info;
241}
242
243/*
244%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
245% %
246% %
247% %
248% D e s t r o y S c r i p t T o k e n I n f o %
249% %
250% %
251% %
252%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
253%
254% DestroyScriptTokenInfo() allocated, initializes and opens the given
255% file stream from which tokens are to be extracted.
256%
257% The format of the DestroyScriptTokenInfo method is:
258%
259% ScriptTokenInfo *DestroyScriptTokenInfo(ScriptTokenInfo *token_info)
260%
261% A description of each parameter follows:
262%
263% o token_info The ScriptTokenInfo structure to be destroyed
264%
265*/
266WandExport ScriptTokenInfo * DestroyScriptTokenInfo(ScriptTokenInfo *token_info)
267{
268 assert(token_info != (ScriptTokenInfo *) NULL);
269 assert(token_info->signature == MagickWandSignature);
270
271 if ( token_info->opened != MagickFalse )
272 fclose(token_info->stream);
273
274 if (token_info->token != (char *) NULL )
275 token_info->token=(char *) RelinquishMagickMemory(token_info->token);
276 token_info=(ScriptTokenInfo *) RelinquishMagickMemory(token_info);
277 return(token_info);
278}
279
280/*
281%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
282% %
283% %
284% %
285% G e t S c r i p t T o k e n %
286% %
287% %
288% %
289%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
290%
291% GetScriptToken() a fairly general, finite state token parser. That returns
292% tokens one at a time, as soon as possible.
293%
294%
295% The format of the GetScriptToken method is:
296%
297% MagickBooleanType GetScriptToken(ScriptTokenInfo *token_info)
298%
299% A description of each parameter follows:
300%
301% o token_info pointer to a structure holding token details
302%
303*/
304/* States of the parser */
305#define IN_WHITE 0
306#define IN_TOKEN 1
307#define IN_QUOTE 2
308#define IN_COMMENT 3
309
310/* Macro to read character from stream
311
312 This also keeps track of the line and column counts.
313 The EOL is defined as either '\r\n', or '\r', or '\n'.
314 A '\r' on its own is converted into a '\n' to correctly handle
315 raw input, typically due to 'copy-n-paste' of text files.
316 But a '\r\n' sequence is left ASIS for string handling
317*/
318#define GetChar(c) \
319{ \
320 c=fgetc(token_info->stream); \
321 token_info->curr_column++; \
322 if ( c == '\r' ) { \
323 c=fgetc(token_info->stream); \
324 ungetc(c,token_info->stream); \
325 c = (c!='\n')?'\n':'\r'; \
326 } \
327 if ( c == '\n' ) \
328 token_info->curr_line++, token_info->curr_column=0; \
329 if (c == EOF ) \
330 break; \
331 if ( (c>='\0' && c<'\a') || (c>'\r' && c<' ' && c!='\033') ) { \
332 token_info->status=TokenStatusBinary; \
333 break; \
334 } \
335}
336/* macro to collect the token characters */
337#define SaveChar(c) \
338{ \
339 if ((size_t) offset >= (token_info->length-1)) { \
340 if (token_info == (ScriptTokenInfo *) NULL) \
341 break; \
342 if ( token_info->length >= MagickPathExtent ) \
343 token_info->length += MagickPathExtent; \
344 else \
345 token_info->length *= 4; \
346 token_info->token=(char *) ResizeQuantumMemory(token_info->token, \
347 token_info->length,sizeof(*token_info->token)); \
348 if ( token_info->token == (char *) NULL ) { \
349 token_info->status=TokenStatusMemoryFailed; \
350 break; \
351 } \
352 } \
353 if ( token_info->token == (char *) NULL ) \
354 token_info->status=TokenStatusMemoryFailed; \
355 else \
356 token_info->token[offset++]=(char) (c); \
357}
358
359WandExport MagickBooleanType GetScriptToken(ScriptTokenInfo *token_info)
360{
361 int
362 quote,
363 c;
364
365 int
366 state;
367
368 ssize_t
369 offset;
370
371 /* EOF - no more tokens! */
372 if (token_info == (ScriptTokenInfo *) NULL)
373 return(MagickFalse);
374 if (token_info->status != TokenStatusOK)
375 {
376 token_info->token[0]='\0';
377 return(MagickFalse);
378 }
379 state=IN_WHITE;
380 quote='\0';
381 offset=0;
382DisableMSCWarning(4127)
383 while(1)
384RestoreMSCWarning
385 {
386 /* get character */
387 GetChar(c);
388
389 /* hash comment handling */
390 if ( state == IN_COMMENT ) {
391 if ( c == '\n' )
392 state=IN_WHITE;
393 continue;
394 }
395 /* comment lines start with '#' anywhere, or ':' or '@' at start of line */
396 if ( state == IN_WHITE )
397 if ( ( c == '#' ) ||
398 ( token_info->curr_column==1 && (c == ':' || c == '@' ) ) )
399 state=IN_COMMENT;
400 /* whitespace token separator character */
401 if (strchr(" \n\r\t",c) != (char *) NULL) {
402 switch (state) {
403 case IN_TOKEN:
404 token_info->token[offset]='\0';
405 return(MagickTrue);
406 case IN_QUOTE:
407 SaveChar(c);
408 break;
409 }
410 continue;
411 }
412 /* quote character */
413 if ( c=='\'' || c =='"' ) {
414 switch (state) {
415 case IN_WHITE:
416 token_info->token_line=token_info->curr_line;
417 token_info->token_column=token_info->curr_column;
418 magick_fallthrough;
419 case IN_TOKEN:
420 state=IN_QUOTE;
421 quote=c;
422 break;
423 case IN_QUOTE:
424 if (c == quote)
425 {
426 state=IN_TOKEN;
427 quote='\0';
428 }
429 else
430 SaveChar(c);
431 break;
432 }
433 continue;
434 }
435 /* escape char (preserve in quotes - unless escaping the same quote) */
436 if (c == '\\')
437 {
438 if ( state==IN_QUOTE && quote == '\'' ) {
439 SaveChar('\\');
440 continue;
441 }
442 GetChar(c);
443 if (c == '\n')
444 switch (state) {
445 case IN_COMMENT:
446 state=IN_WHITE; /* end comment */
447 magick_fallthrough;
448 case IN_QUOTE:
449 if (quote != '"')
450 break; /* in double quotes only */
451 magick_fallthrough;
452 case IN_WHITE:
453 case IN_TOKEN:
454 continue; /* line continuation - remove line feed */
455 }
456 switch (state) {
457 case IN_WHITE:
458 token_info->token_line=token_info->curr_line;
459 token_info->token_column=token_info->curr_column;
460 state=IN_TOKEN;
461 break;
462 case IN_QUOTE:
463 if (c != quote && c != '\\')
464 SaveChar('\\');
465 break;
466 }
467 SaveChar(c);
468 continue;
469 }
470 /* ordinary character */
471 switch (state) {
472 case IN_WHITE:
473 token_info->token_line=token_info->curr_line;
474 token_info->token_column=token_info->curr_column;
475 state=IN_TOKEN;
476 magick_fallthrough;
477 case IN_TOKEN:
478 case IN_QUOTE:
479 SaveChar(c);
480 break;
481 case IN_COMMENT:
482 break;
483 }
484 }
485 /* input stream has EOF or produced a fatal error */
486 token_info->token[offset]='\0';
487 if ( token_info->status != TokenStatusOK )
488 return(MagickFalse); /* fatal condition - no valid token */
489 token_info->status = TokenStatusEOF;
490 if ( state == IN_QUOTE)
491 token_info->status = TokenStatusBadQuotes;
492 if ( state == IN_TOKEN)
493 return(MagickTrue); /* token with EOF at end - no problem */
494 return(MagickFalse); /* in white space or in quotes - invalid token */
495}