1 /* $NetBSD: for.c,v 1.168 2022/06/12 16:09:21 rillig Exp $ */
4 * Copyright (c) 1992, The Regents of the University of California.
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28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * Handling of .for/.endfor loops in a makefile.
35 * For loops have the form:
37 * .for <varname...> in <value...>
41 * When a .for line is parsed, the following lines are copied to the body of
42 * the .for loop, until the corresponding .endfor line is reached. In this
43 * phase, the body is not yet evaluated. This also applies to any nested
46 * After reaching the .endfor, the values from the .for line are grouped
47 * according to the number of variables. For each such group, the unexpanded
48 * body is scanned for variable expressions, and those that match the
49 * variable names are replaced with expressions of the form ${:U...}. After
50 * that, the body is treated like a file from an .include directive.
53 * For_Eval Evaluate the loop in the passed line.
55 * For_Run Run accumulated loop
60 /* "@(#)for.c 8.1 (Berkeley) 6/6/93" */
61 MAKE_RCSID("$NetBSD: for.c,v 1.168 2022/06/12 16:09:21 rillig Exp $");
64 typedef struct ForLoop {
65 Vector /* of 'char *' */ vars; /* Iteration variables */
66 SubstringWords items; /* Substitution items */
67 Buffer body; /* Unexpanded body of the loop */
68 unsigned int nextItem; /* Where to continue iterating */
72 static ForLoop *accumFor; /* Loop being accumulated */
78 ForLoop *f = bmake_malloc(sizeof *f);
80 Vector_Init(&f->vars, sizeof(char *));
81 SubstringWords_Init(&f->items);
89 ForLoop_Free(ForLoop *f)
91 while (f->vars.len > 0)
92 free(*(char **)Vector_Pop(&f->vars));
93 Vector_Done(&f->vars);
95 SubstringWords_Free(f->items);
102 ForLoop_Details(ForLoop *f)
106 const Substring *items;
110 vars = f->vars.items;
111 assert(f->nextItem >= n);
112 items = f->items.words + f->nextItem - n;
115 for (i = 0; i < n; i++) {
117 Buf_AddStr(&buf, ", ");
118 Buf_AddStr(&buf, vars[i]);
119 Buf_AddStr(&buf, " = ");
120 Buf_AddBytesBetween(&buf, items[i].start, items[i].end);
122 return Buf_DoneData(&buf);
126 ForLoop_ParseVarnames(ForLoop *f, const char **pp)
133 cpp_skip_whitespace(&p);
135 Parse_Error(PARSE_FATAL, "missing `in' in for");
140 * XXX: This allows arbitrary variable names;
141 * see directive-for.mk.
143 for (len = 1; p[len] != '\0' && !ch_isspace(p[len]); len++)
146 if (len == 2 && p[0] == 'i' && p[1] == 'n') {
151 *(char **)Vector_Push(&f->vars) = bmake_strldup(p, len);
155 if (f->vars.len == 0) {
156 Parse_Error(PARSE_FATAL, "no iteration variables in for");
165 ForLoop_ParseItems(ForLoop *f, const char *p)
169 cpp_skip_whitespace(&p);
171 if (Var_Subst(p, SCOPE_GLOBAL, VARE_WANTRES, &items) != VPR_OK) {
172 Parse_Error(PARSE_FATAL, "Error in .for loop items");
176 f->items = Substring_Words(items, false);
179 if (f->items.len == 1 && Substring_IsEmpty(f->items.words[0]))
180 f->items.len = 0; /* .for var in ${:U} */
182 if (f->items.len % f->vars.len != 0) {
183 Parse_Error(PARSE_FATAL,
184 "Wrong number of words (%u) in .for "
185 "substitution list with %u variables",
186 (unsigned)f->items.len, (unsigned)f->vars.len);
196 return p[0] == 'f' && p[1] == 'o' && p[2] == 'r' && ch_isspace(p[3]);
200 IsEndfor(const char *p)
202 return p[0] == 'e' && strncmp(p, "endfor", 6) == 0 &&
203 (p[6] == '\0' || ch_isspace(p[6]));
207 * Evaluate the for loop in the passed line. The line looks like this:
208 * .for <varname...> in <value...>
211 * 0 not a .for directive
212 * 1 found a .for directive
213 * -1 erroneous .for directive
216 For_Eval(const char *line)
221 p = line + 1; /* skip the '.' */
222 cpp_skip_whitespace(&p);
228 if (!ForLoop_ParseVarnames(f, &p)) {
232 if (!ForLoop_ParseItems(f, p))
233 f->items.len = 0; /* don't iterate */
237 } else if (IsEndfor(p)) {
238 Parse_Error(PARSE_FATAL, "for-less endfor");
245 * Add another line to the .for loop that is being built up.
246 * Returns false when the matching .endfor is reached.
249 For_Accum(const char *line, int *forLevel)
251 const char *p = line;
255 cpp_skip_whitespace(&p);
258 DEBUG1(FOR, "For: end for %d\n", *forLevel);
259 if (--*forLevel == 0)
261 } else if (IsFor(p)) {
263 DEBUG1(FOR, "For: new loop %d\n", *forLevel);
267 Buf_AddStr(&accumFor->body, line);
268 Buf_AddByte(&accumFor->body, '\n');
273 * When the body of a '.for i' loop is prepared for an iteration, each
274 * occurrence of $i in the body is replaced with ${:U...}, inserting the
275 * value of the item. If this item contains a '$', it may be the start of a
276 * variable expression. This expression is copied verbatim, its length is
277 * determined here, in a rather naive way, ignoring escape characters and
278 * funny delimiters in modifiers like ':S}from}to}'.
281 ExprLen(const char *s, const char *e)
283 char expr_open, expr_close;
288 return 0; /* just escape the '$' */
291 if (expr_open == '(')
293 else if (expr_open == '{')
296 return 1; /* Single char variable */
299 for (p = s + 1; p != e; p++) {
302 else if (*p == expr_close && --depth == 0)
303 return (size_t)(p + 1 - s);
306 /* Expression end not found, escape the $ */
311 * The .for loop substitutes the items as ${:U<value>...}, which means
312 * that characters that break this syntax must be backslash-escaped.
315 NeedsEscapes(Substring value, char endc)
319 for (p = value.start; p != value.end; p++) {
320 if (*p == ':' || *p == '$' || *p == '\\' || *p == endc ||
328 * While expanding the body of a .for loop, write the item in the ${:U...}
329 * expression, escaping characters as needed. The result is later unescaped
330 * by ApplyModifier_Defined.
333 AddEscaped(Buffer *cmds, Substring item, char endc)
338 if (!NeedsEscapes(item, endc)) {
339 Buf_AddBytesBetween(cmds, item.start, item.end);
343 for (p = item.start; p != item.end;) {
346 size_t len = ExprLen(p + 1, item.end);
349 * XXX: Should a '\' be added here?
350 * See directive-for-escape.mk, ExprLen.
352 Buf_AddBytes(cmds, p, 1 + len);
356 Buf_AddByte(cmds, '\\');
357 } else if (ch == ':' || ch == '\\' || ch == endc)
358 Buf_AddByte(cmds, '\\');
359 else if (ch == '\n') {
360 Parse_Error(PARSE_FATAL, "newline in .for value");
361 ch = ' '; /* prevent newline injection */
363 Buf_AddByte(cmds, ch);
369 * When expanding the body of a .for loop, replace the variable name of an
370 * expression like ${i} or ${i:...} or $(i) or $(i:...) with ":Uvalue".
373 ForLoop_SubstVarLong(ForLoop *f, unsigned int firstItem, Buffer *body,
374 const char **pp, char endc, const char **inout_mark)
377 const char *start = *pp;
378 const char **vars = Vector_Get(&f->vars, 0);
380 for (i = 0; i < f->vars.len; i++) {
381 const char *p = start;
383 if (!cpp_skip_string(&p, vars[i]))
385 /* XXX: why test for backslash here? */
386 if (*p != ':' && *p != endc && *p != '\\')
390 * Found a variable match. Skip over the variable name and
391 * instead add ':U<value>' to the current body.
393 Buf_AddBytesBetween(body, *inout_mark, start);
394 Buf_AddStr(body, ":U");
395 AddEscaped(body, f->items.words[firstItem + i], endc);
404 * When expanding the body of a .for loop, replace single-character
405 * variable expressions like $i with their ${:U...} expansion.
408 ForLoop_SubstVarShort(ForLoop *f, unsigned int firstItem, Buffer *body,
409 const char *p, const char **inout_mark)
415 /* Skip $$ and stupid ones. */
416 if (ch == '}' || ch == ')' || ch == ':' || ch == '$')
419 vars = Vector_Get(&f->vars, 0);
420 for (i = 0; i < f->vars.len; i++) {
421 const char *varname = vars[i];
422 if (varname[0] == ch && varname[1] == '\0')
428 Buf_AddBytesBetween(body, *inout_mark, p);
431 /* Replace $<ch> with ${:U<value>} */
432 Buf_AddStr(body, "{:U");
433 AddEscaped(body, f->items.words[firstItem + i], '}');
434 Buf_AddByte(body, '}');
438 * Compute the body for the current iteration by copying the unexpanded body,
439 * replacing the expressions for the iteration variables on the way.
441 * Using variable expressions ensures that the .for loop can't generate
442 * syntax, and that the later parsing will still see a variable.
443 * This code assumes that the variable with the empty name will never be
444 * defined, see unit-tests/varname-empty.mk for more details.
446 * The detection of substitutions of the loop control variables is naive.
447 * Many of the modifiers use '\$' instead of '$$' to escape '$', so it is
448 * possible to contrive a makefile where an unwanted substitution happens.
451 ForLoop_SubstBody(ForLoop *f, unsigned int firstItem, Buffer *body)
454 const char *mark; /* where the last substitution left off */
459 end = f->body.data + f->body.len;
460 for (p = mark; (p = strchr(p, '$')) != NULL;) {
461 if (p[1] == '{' || p[1] == '(') {
462 char endc = p[1] == '{' ? '}' : ')';
464 ForLoop_SubstVarLong(f, firstItem, body,
466 } else if (p[1] != '\0') {
467 ForLoop_SubstVarShort(f, firstItem, body,
474 Buf_AddBytesBetween(body, mark, end);
478 * Compute the body for the current iteration by copying the unexpanded body,
479 * replacing the expressions for the iteration variables on the way.
482 For_NextIteration(ForLoop *f, Buffer *body)
484 if (f->nextItem == f->items.len)
487 f->nextItem += (unsigned int)f->vars.len;
488 ForLoop_SubstBody(f, f->nextItem - (unsigned int)f->vars.len, body);
489 DEBUG1(FOR, "For: loop body:\n%s", body->data);
493 /* Run the .for loop, imitating the actions of an include file. */
495 For_Run(unsigned headLineno, unsigned bodyReadLines)
498 ForLoop *f = accumFor;
501 if (f->items.len > 0) {
503 Parse_PushInput(NULL, headLineno, bodyReadLines, buf, f);