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pg(1): start work on a quoted strtok(3) and internal environment

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This commit is contained in:
dtb 2024-04-26 19:08:48 -06:00
parent eb454a6dad
commit 7142994367
Signed by: trinity
GPG Key ID: 31FF85CCB6DC7641
1 changed files with 77 additions and 11 deletions
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88
src/pg.c
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@ -6,7 +6,7 @@
* the terms of the GNU Affero General Public License as published by the Free
* Software Foundation, either version 3 of the License, or (at your option) any
* later version.
*
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
* FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more
@ -42,6 +42,70 @@ static FILE *input;
static char *prompt = ": ";
static char *program_name = "pg";
static char *permute_out(char *str, size_t index){
size_t j;
for(j = index; str[j - 1] != '\0'; ++j)
str[j - 1] = str[j];
return str;
}
/* strtok(3p), but supports double-quotes and escapes (but only for escaping
* quotes). UTF-8 is safe only in str. Unmatched quotes in str are considered
* literal. The behavior of strtok_quoted when '"' or '\\' are in sep is
* undefined. */
/* TODO: Seems to only ever return NULL. */
static char *strtok_quoted(char *str, char *sep){
static char *s;
size_t i;
size_t j;
if(str != NULL)
s = str;
while(strchr(sep, *s) == NULL)
if(*++s == '\0')
return NULL; /* no remaining characters except seperators */
{
char in_escape;
int in_quotes;
in_escape = 0;
in_quotes = -1;
for(i = 0; s[i] != '\0'; ++i)
switch(s[i]){
case '\\':
if(in_escape)
permute_out(s, i--);
in_escape = !in_escape;
break;
case '"':
if(in_escape){
s[i] = s[i - 1];
permute_out(s, i--);
}else if(in_quotes != -1){
permute_out(s, in_quotes);
--i;
permute_out(s, i--);
in_quotes = -1;
}else
in_quotes = i;
break;
case '\0':
return s;
default:
if(!in_escape && strchr(sep, s[i]) != NULL){
s[i] = '\0';
return s;
}
}
}
return s;
}
/* Page at most l bytes from f without consideration of a buffer (print them to
* stdout). */
static int pg_b_u(FILE *f, size_t l){
@ -66,8 +130,8 @@ static int pg_l_u(FILE *f, size_t l, char nl){
return c;
}
static int cmd_quit(int argc, char **argv){ return EX_UNAVAILABLE; }
static int cmd_default_page(int argc, char **argv){
static int cmd_quit(int argc, char **argv, char **envp){return EX_UNAVAILABLE;}
static int cmd_default_page(int argc, char **argv, char **envp){
if(argc > 1) /* This shouldn't be possible. */
return EX_USAGE;
@ -82,11 +146,11 @@ static int cmd_default_page(int argc, char **argv){
else
return EX_SOFTWARE;
}
static int cmd_page_down_lines(int argc, char **argv){
static int cmd_page_down_lines(int argc, char **argv, char **envp){
switch(argc){
case 1:
return cmd_default_page(argc, argv);
return cmd_default_page(argc, argv, envp);
case 2: /* not implemented */
default:
fprintf(stderr, "Usage: %s" /*" (lines)"*/ "\n", argv[0]);
@ -95,13 +159,15 @@ static int cmd_page_down_lines(int argc, char **argv){
}
/* A CmdMap must be NULL-terminated. */
static struct CmdMap{ char *name; int (*fn)(int, char **); } builtins[] = {
static struct CmdMap{ char *name; int (*fn)(int, char **, char **); }
builtins[] = {
{ "", cmd_default_page },
{ "+", cmd_page_down_lines },
/* don't make the user feel trapped */
{ "exit", cmd_quit }, { "q", cmd_quit }, { ":q", cmd_quit },
{ ":q!", cmd_quit }, { "quit", cmd_quit }, { "ZZ", cmd_quit },
{ ":q", cmd_quit }, { ":q!", cmd_quit },
{ "exit", cmd_quit }, { "q", cmd_quit }, { "Q", cmd_quit },
{ "quit", cmd_quit }, { "ZZ", cmd_quit },
{ NULL, NULL }
};
@ -109,7 +175,7 @@ static struct CmdMap{ char *name; int (*fn)(int, char **); } builtins[] = {
#define ARGV_MAX 10
/* Find and execute the command in the command map, given a corresponding
* command line. */
static int cmdline_exec(struct CmdMap *map, char *cmdline){
static int cmdline_exec(struct CmdMap *map, char *cmdline, char **envp){
/* Command line word splitting is naive and based on whitespace ONLY; no
* fancy quoting or escaping here. Adding that would (ideally) entail
* replacing strtok(3) with something specific to this task. */
@ -128,7 +194,7 @@ static int cmdline_exec(struct CmdMap *map, char *cmdline){
for(; map->name != NULL; map = &map[1])
if(strcmp(map->name, argv[0]) == 0)
return map->fn(argc, argv);
return map->fn(argc, argv, envp);
fprintf(stderr, "%s: %s: not found\n", program_name, argv[0]);
return EX_USAGE;
@ -182,7 +248,7 @@ int main(int argc, char *argv[]){
return EX_OK;
{ int r;
switch((r = cmdline_exec(builtins, (char *)cmd))){
switch((r = cmdline_exec(builtins, (char *)cmd, NULL))){
case EX_OK: case EX_USAGE: break;
case EX_UNAVAILABLE: return EX_OK;
default: return r;