freebsd-nq/contrib/bmake/for.c

518 lines
12 KiB
C

/* $NetBSD: for.c,v 1.142 2021/04/03 11:08:40 rillig Exp $ */
/*
* Copyright (c) 1992, The Regents of the University of California.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
/*
* Handling of .for/.endfor loops in a makefile.
*
* For loops have the form:
*
* .for <varname...> in <value...>
* # the body
* .endfor
*
* When a .for line is parsed, the following lines are copied to the body of
* the .for loop, until the corresponding .endfor line is reached. In this
* phase, the body is not yet evaluated. This also applies to any nested
* .for loops.
*
* After reaching the .endfor, the values from the .for line are grouped
* according to the number of variables. For each such group, the unexpanded
* body is scanned for variable expressions, and those that match the variable
* names are replaced with expressions of the form ${:U...} or $(:U...).
* After that, the body is treated like a file from an .include directive.
*
* Interface:
* For_Eval Evaluate the loop in the passed line.
*
* For_Run Run accumulated loop
*/
#include "make.h"
/* "@(#)for.c 8.1 (Berkeley) 6/6/93" */
MAKE_RCSID("$NetBSD: for.c,v 1.142 2021/04/03 11:08:40 rillig Exp $");
/* One of the variables to the left of the "in" in a .for loop. */
typedef struct ForVar {
char *name;
size_t nameLen;
} ForVar;
typedef struct ForLoop {
Buffer body; /* Unexpanded body of the loop */
Vector /* of ForVar */ vars; /* Iteration variables */
Words items; /* Substitution items */
Buffer curBody; /* Expanded body of the current iteration */
/* Is any of the names 1 character long? If so, when the variable values
* are substituted, the parser must handle $V expressions as well, not
* only ${V} and $(V). */
bool short_var;
unsigned int sub_next; /* Where to continue iterating */
} ForLoop;
static ForLoop *accumFor; /* Loop being accumulated */
static int forLevel = 0; /* Nesting level */
static ForLoop *
ForLoop_New(void)
{
ForLoop *f = bmake_malloc(sizeof *f);
Buf_Init(&f->body);
Vector_Init(&f->vars, sizeof(ForVar));
f->items.words = NULL;
f->items.freeIt = NULL;
Buf_Init(&f->curBody);
f->short_var = false;
f->sub_next = 0;
return f;
}
static void
ForLoop_Free(ForLoop *f)
{
Buf_Done(&f->body);
while (f->vars.len > 0) {
ForVar *var = Vector_Pop(&f->vars);
free(var->name);
}
Vector_Done(&f->vars);
Words_Free(f->items);
Buf_Done(&f->curBody);
free(f);
}
static void
ForLoop_AddVar(ForLoop *f, const char *name, size_t len)
{
ForVar *var = Vector_Push(&f->vars);
var->name = bmake_strldup(name, len);
var->nameLen = len;
}
static bool
ForLoop_ParseVarnames(ForLoop *f, const char **pp)
{
const char *p = *pp;
for (;;) {
size_t len;
cpp_skip_whitespace(&p);
if (*p == '\0') {
Parse_Error(PARSE_FATAL, "missing `in' in for");
return false;
}
/*
* XXX: This allows arbitrary variable names;
* see directive-for.mk.
*/
for (len = 1; p[len] != '\0' && !ch_isspace(p[len]); len++)
continue;
if (len == 2 && p[0] == 'i' && p[1] == 'n') {
p += 2;
break;
}
if (len == 1)
f->short_var = true;
ForLoop_AddVar(f, p, len);
p += len;
}
if (f->vars.len == 0) {
Parse_Error(PARSE_FATAL, "no iteration variables in for");
return false;
}
*pp = p;
return true;
}
static bool
ForLoop_ParseItems(ForLoop *f, const char *p)
{
char *items;
cpp_skip_whitespace(&p);
if (Var_Subst(p, SCOPE_GLOBAL, VARE_WANTRES, &items) != VPR_OK) {
Parse_Error(PARSE_FATAL, "Error in .for loop items");
return false;
}
f->items = Str_Words(items, false);
free(items);
if (f->items.len == 1 && f->items.words[0][0] == '\0')
f->items.len = 0; /* .for var in ${:U} */
if (f->items.len != 0 && f->items.len % f->vars.len != 0) {
Parse_Error(PARSE_FATAL,
"Wrong number of words (%u) in .for "
"substitution list with %u variables",
(unsigned)f->items.len, (unsigned)f->vars.len);
return false;
}
return true;
}
static bool
IsFor(const char *p)
{
return p[0] == 'f' && p[1] == 'o' && p[2] == 'r' && ch_isspace(p[3]);
}
static bool
IsEndfor(const char *p)
{
return p[0] == 'e' && strncmp(p, "endfor", 6) == 0 &&
(p[6] == '\0' || ch_isspace(p[6]));
}
/*
* Evaluate the for loop in the passed line. The line looks like this:
* .for <varname...> in <value...>
*
* Input:
* line Line to parse
*
* Results:
* 0: Not a .for statement, parse the line
* 1: We found a for loop
* -1: A .for statement with a bad syntax error, discard.
*/
int
For_Eval(const char *line)
{
ForLoop *f;
const char *p;
p = line + 1; /* skip the '.' */
cpp_skip_whitespace(&p);
if (!IsFor(p)) {
if (IsEndfor(p)) {
Parse_Error(PARSE_FATAL, "for-less endfor");
return -1;
}
return 0;
}
p += 3;
f = ForLoop_New();
if (!ForLoop_ParseVarnames(f, &p)) {
ForLoop_Free(f);
return -1;
}
if (!ForLoop_ParseItems(f, p)) {
/* Continue parsing the .for loop, but don't iterate. */
f->items.len = 0;
}
accumFor = f;
forLevel = 1;
return 1;
}
/*
* Add another line to the .for loop that is being built up.
* Returns false when the matching .endfor is reached.
*/
bool
For_Accum(const char *line)
{
const char *p = line;
if (*p == '.') {
p++;
cpp_skip_whitespace(&p);
if (IsEndfor(p)) {
DEBUG1(FOR, "For: end for %d\n", forLevel);
if (--forLevel <= 0)
return false;
} else if (IsFor(p)) {
forLevel++;
DEBUG1(FOR, "For: new loop %d\n", forLevel);
}
}
Buf_AddStr(&accumFor->body, line);
Buf_AddByte(&accumFor->body, '\n');
return true;
}
static size_t
for_var_len(const char *var)
{
char ch, var_start, var_end;
int depth;
size_t len;
var_start = *var;
if (var_start == '\0')
/* just escape the $ */
return 0;
if (var_start == '(')
var_end = ')';
else if (var_start == '{')
var_end = '}';
else
return 1; /* Single char variable */
depth = 1;
for (len = 1; (ch = var[len++]) != '\0';) {
if (ch == var_start)
depth++;
else if (ch == var_end && --depth == 0)
return len;
}
/* Variable end not found, escape the $ */
return 0;
}
/*
* The .for loop substitutes the items as ${:U<value>...}, which means
* that characters that break this syntax must be backslash-escaped.
*/
static bool
NeedsEscapes(const char *value, char endc)
{
const char *p;
for (p = value; *p != '\0'; p++) {
if (*p == ':' || *p == '$' || *p == '\\' || *p == endc)
return true;
}
return false;
}
/*
* While expanding the body of a .for loop, write the item in the ${:U...}
* expression, escaping characters as needed.
*
* The result is later unescaped by ApplyModifier_Defined.
*/
static void
Buf_AddEscaped(Buffer *cmds, const char *item, char endc)
{
char ch;
if (!NeedsEscapes(item, endc)) {
Buf_AddStr(cmds, item);
return;
}
/* Escape ':', '$', '\\' and 'endc' - these will be removed later by
* :U processing, see ApplyModifier_Defined. */
while ((ch = *item++) != '\0') {
if (ch == '$') {
size_t len = for_var_len(item);
if (len != 0) {
Buf_AddBytes(cmds, item - 1, len + 1);
item += len;
continue;
}
Buf_AddByte(cmds, '\\');
} else if (ch == ':' || ch == '\\' || ch == endc)
Buf_AddByte(cmds, '\\');
Buf_AddByte(cmds, ch);
}
}
/*
* While expanding the body of a .for loop, replace the variable name of an
* expression like ${i} or ${i:...} or $(i) or $(i:...) with ":Uvalue".
*/
static void
ForLoop_SubstVarLong(ForLoop *f, const char **pp, const char *bodyEnd,
char endc, const char **inout_mark)
{
size_t i;
const char *p = *pp;
for (i = 0; i < f->vars.len; i++) {
ForVar *forVar = Vector_Get(&f->vars, i);
char *varname = forVar->name;
size_t varnameLen = forVar->nameLen;
if (varnameLen >= (size_t)(bodyEnd - p))
continue;
if (memcmp(p, varname, varnameLen) != 0)
continue;
/* XXX: why test for backslash here? */
if (p[varnameLen] != ':' && p[varnameLen] != endc &&
p[varnameLen] != '\\')
continue;
/*
* Found a variable match. Skip over the variable name and
* instead add ':U<value>' to the current body.
*/
Buf_AddBytesBetween(&f->curBody, *inout_mark, p);
Buf_AddStr(&f->curBody, ":U");
Buf_AddEscaped(&f->curBody,
f->items.words[f->sub_next + i], endc);
p += varnameLen;
*inout_mark = p;
*pp = p;
return;
}
}
/*
* While expanding the body of a .for loop, replace single-character
* variable expressions like $i with their ${:U...} expansion.
*/
static void
ForLoop_SubstVarShort(ForLoop *f, const char *p, const char **inout_mark)
{
const char ch = *p;
ForVar *vars;
size_t i;
/* Skip $$ and stupid ones. */
if (!f->short_var || strchr("}):$", ch) != NULL)
return;
vars = Vector_Get(&f->vars, 0);
for (i = 0; i < f->vars.len; i++) {
const char *varname = vars[i].name;
if (varname[0] == ch && varname[1] == '\0')
goto found;
}
return;
found:
/* Replace $<ch> with ${:U<value>} */
Buf_AddBytesBetween(&f->curBody, *inout_mark, p), *inout_mark = p + 1;
Buf_AddStr(&f->curBody, "{:U");
Buf_AddEscaped(&f->curBody, f->items.words[f->sub_next + i], '}');
Buf_AddByte(&f->curBody, '}');
}
/*
* Compute the body for the current iteration by copying the unexpanded body,
* replacing the expressions for the iteration variables on the way.
*
* Using variable expressions ensures that the .for loop can't generate
* syntax, and that the later parsing will still see a variable.
* This code assumes that the variable with the empty name will never be
* defined, see unit-tests/varname-empty.mk for more details.
*
* The detection of substitutions of the loop control variables is naive.
* Many of the modifiers use '\' to escape '$' (not '$'), so it is possible
* to contrive a makefile where an unwanted substitution happens.
*/
static void
ForLoop_SubstBody(ForLoop *f)
{
const char *p, *bodyEnd;
const char *mark; /* where the last replacement left off */
Buf_Empty(&f->curBody);
mark = f->body.data;
bodyEnd = f->body.data + f->body.len;
for (p = mark; (p = strchr(p, '$')) != NULL;) {
if (p[1] == '{' || p[1] == '(') {
p += 2;
ForLoop_SubstVarLong(f, &p, bodyEnd,
p[-1] == '{' ? '}' : ')', &mark);
} else if (p[1] != '\0') {
ForLoop_SubstVarShort(f, p + 1, &mark);
p += 2;
} else
break;
}
Buf_AddBytesBetween(&f->curBody, mark, bodyEnd);
}
/*
* Compute the body for the current iteration by copying the unexpanded body,
* replacing the expressions for the iteration variables on the way.
*/
static char *
ForReadMore(void *v_arg, size_t *out_len)
{
ForLoop *f = v_arg;
if (f->sub_next == f->items.len) {
/* No more iterations */
ForLoop_Free(f);
return NULL;
}
ForLoop_SubstBody(f);
DEBUG1(FOR, "For: loop body:\n%s", f->curBody.data);
f->sub_next += (unsigned int)f->vars.len;
*out_len = f->curBody.len;
return f->curBody.data;
}
/* Run the .for loop, imitating the actions of an include file. */
void
For_Run(int lineno)
{
ForLoop *f = accumFor;
accumFor = NULL;
if (f->items.len == 0) {
/*
* Nothing to expand - possibly due to an earlier syntax
* error.
*/
ForLoop_Free(f);
return;
}
Parse_SetInput(NULL, lineno, -1, ForReadMore, f);
}