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make(1): split Var_Subst into easily understandable functions

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Extracting the character-level details makes the essence of Var_Subst
visible in the code, which is to iterate over the given text, handling a
few types of tokens.
This commit is contained in:
rillig 2020-12-27 11:03:00 +00:00
parent fab83987ed
commit 7c7dae763b
1 changed files with 39 additions and 29 deletions
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68
usr.bin/make/var.c
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@ -1,4 +1,4 @@
/* $NetBSD: var.c,v 1.767 2020/12/27 10:53:23 rillig Exp $ */
/* $NetBSD: var.c,v 1.768 2020/12/27 11:03:00 rillig Exp $ */
/*
* Copyright (c) 1988, 1989, 1990, 1993
@ -131,7 +131,7 @@
#include "metachar.h"
/* "@(#)var.c 8.3 (Berkeley) 3/19/94" */
MAKE_RCSID("$NetBSD: var.c,v 1.767 2020/12/27 10:53:23 rillig Exp $");
MAKE_RCSID("$NetBSD: var.c,v 1.768 2020/12/27 11:03:00 rillig Exp $");
typedef enum VarFlags {
VAR_NONE = 0,
@ -4177,8 +4177,21 @@ Var_Parse(const char **pp, GNode *ctxt, VarEvalFlags eflags, FStr *out_val)
}
static void
VarSubstNested(const char **pp, Buffer *buf, GNode *ctxt,
VarEvalFlags eflags, Boolean *inout_errorReported)
VarSubstDollarDollar(const char **pp, Buffer *res, VarEvalFlags eflags)
{
/*
* A dollar sign may be escaped with another dollar
* sign.
*/
if (save_dollars && (eflags & VARE_KEEP_DOLLAR))
Buf_AddByte(res, '$');
Buf_AddByte(res, '$');
*pp += 2;
}
static void
VarSubstExpr(const char **pp, Buffer *buf, GNode *ctxt,
VarEvalFlags eflags, Boolean *inout_errorReported)
{
const char *p = *pp;
const char *nested_p = p;
@ -4229,6 +4242,22 @@ VarSubstNested(const char **pp, Buffer *buf, GNode *ctxt,
*pp = p;
}
/*
* Skip as many characters as possible -- either to the end of the string
* or to the next dollar sign (variable expression).
*/
static void
VarSubstPlain(const char **pp, Buffer *res)
{
const char *p = *pp;
const char *start = p;
for (p++; *p != '$' && *p != '\0'; p++)
continue;
Buf_AddBytesBetween(res, start, p);
*pp = p;
}
/* Expand all variable expressions like $V, ${VAR}, $(VAR:Modifiers) in the
* given string.
*
@ -4254,31 +4283,12 @@ Var_Subst(const char *str, GNode *ctxt, VarEvalFlags eflags, char **out_res)
errorReported = FALSE;
while (*p != '\0') {
if (p[0] == '$' && p[1] == '$') {
/*
* A dollar sign may be escaped with another dollar
* sign.
*/
if (save_dollars && (eflags & VARE_KEEP_DOLLAR))
Buf_AddByte(&res, '$');
Buf_AddByte(&res, '$');
p += 2;
} else if (p[0] == '$') {
VarSubstNested(&p, &res, ctxt, eflags, &errorReported);
} else {
/*
* Skip as many characters as possible -- either to
* the end of the string or to the next dollar sign
* (variable expression).
*/
const char *plainStart = p;
for (p++; *p != '$' && *p != '\0'; p++)
continue;
Buf_AddBytesBetween(&res, plainStart, p);
}
if (p[0] == '$' && p[1] == '$')
VarSubstDollarDollar(&p, &res, eflags);
else if (p[0] == '$')
VarSubstExpr(&p, &res, ctxt, eflags, &errorReported);
else
VarSubstPlain(&p, &res);
}
*out_res = Buf_DestroyCompact(&res);