pg(1): more work on strtok_quoted

src/pg.c

@@ -23,7 +23,7 @@
                     * fprintf(3), fputc(3), perror(3), stderr, stdin, stdout,
                     * EOF, FILE, NULL */
 #include <stdlib.h> /* size_t */
-#include <string.h> /* strchr(3), strcmp(3), strerror(3), strtok(3) */
+#include <string.h> /* strchr(3), strcmp(3) */
 #include <unistd.h> /* getopt(3) */
 
 /* Commands start with cmd_. They take an argc and NULL-terminated argv, like
@@ -36,6 +36,14 @@
 
 static char *whitespace = " \n\r\t\v";
 
+//static
+struct Tube {
+	char *name;   // command line
+	FILE *in;     // process stdin
+	FILE *out;    // process stdoout
+	size_t index; // in pipeline
+};
+
 static struct {
 	size_t quantity;
 	enum { LINES = 0, BYTES = 1 } type;
@@ -45,57 +53,69 @@ static char *prompt = ": ";
 static char *program_name = "pg";
 
 static char *
-permute_out(char *str, size_t i) {
+permute_out(char *s, size_t i) {
 	for (
 		;
-		str[i - 1] != '\0';
-		str[i - 1] = str[i], ++i
+		s[i] != '\0';
+		s[i] = s[i + 1], ++i
 	);
 
-	return str;
+	return s;
 }
 
 /* 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. */
+ * quotes).  Unmatched quotes in str are considered literal. The behavior of
+ * strtok_quoted when '\'', '"', or '\\' are in sep is undefined. Use of UTF-8
+ * separators with strtok_quoted is undefined. */
 static char *
 strtok_quoted(char *str, char *sep) {
 	static char *s;
 
 	if (str != NULL) { s = str; }
 
-	while (strchr(sep, *s) == NULL) {
-		if(*++s == '\0') { return NULL; } /* no remaining except seps */
+	while (strchr(sep, *s) != NULL) { // skip beginning whitespace
+		if(*++s == '\0') { return NULL; } // no remaining except seps
 	}
 
 	{
-		bool in_escape = 0;
-		int in_quotes = -1; /* index of quote, or -1 if none */
+		bool in_escape = 0; // previous char was '\\'
+		char quote = '\0';  // quotation mark used, or '\0' if none
 
-		for (size_t i = 0; s[i] != '\0'; ++i)
+		for (int i = 0; s[i] != '\0'; ++i)
 			switch (s[i]) {
 				case '\\':
-					/* if literal \\, permute out a backslash */
-					if (in_escape) { permute_out(s, i--); }
+					// if literal "\\", permute out a backslash
+					if (in_escape) { (void)permute_out(s, i--); }
 					in_escape = !in_escape;
 					break;
-				case '"':
+				case '\'': case '"':
 					if (in_escape) { // \"
 						s[i] = s[i - 1];
 						(void)permute_out(s, i--); // permute out backslash
-					} else if (in_quotes != -1) {
-						(void)permute_out(s, in_quotes); --i; // first "
-						(void)permute_out(s, i--); // second "
-						in_quotes = -1;
-					} else { in_quotes = i; }
+					} else if (s[i] == quote) {
+						quote = '\0';
+						(void)permute_out(s, i--); // second quote
+					} else {
+						quote = s[i];
+						if (strchr(&s[i + 1], quote) != NULL) { // has a match
+							(void)permute_out(s, i--); // permute out lquote
+						}
+					}
 					break;
 				case '\0': return s;
 				default:
-					if (!in_escape && strchr(sep, s[i]) != NULL) {
-						s[i] = '\0';
-						return s;
+					if (!in_escape
+					    	&& quote == '\0'
+					    	&& (strchr(sep, s[i]) != NULL || s[i] == '\0')) {
+						char *t; // start of current token
+
+						t = s;
+						s = s[i] != '\0'
+							? &t[i + 1] // store start of next token,
+							: &t[i];    // or the address of the nul if found
+						s[i] = '\0'; // NUL terminate current token
+
+						return t;
 					}
 			}
 	}
@@ -173,19 +193,16 @@ builtins[] = {
  * command line. */
 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. */
 	static int argc;
 	static char *argv[ARGV_MAX];
 
-	if ((argv[(argc = 0)] = strtok(cmdline, whitespace)) == NULL) {
+	if ((argv[(argc = 0)] = strtok_quoted(cmdline, whitespace)) == NULL) {
 		while (cmdline[0] != '\0') { cmdline = &cmdline[1]; }
 		argv[argc] = cmdline;
 		argv[++argc] = NULL;
 	} else {
 		while (
-			(argv[++argc] = strtok(NULL, whitespace)) != NULL
+			(argv[++argc] = strtok_quoted(NULL, whitespace)) != NULL
 			&& argc < ARGV_MAX
 		);
 	}
@@ -231,33 +248,28 @@ int main(int argc, char *argv[]) {
 		}
 	}
 
-	if(argc > optind) { return usage(program_name); }
+	if (argc > optind) { return usage(program_name); }
 
 
 	if ((t = fopen("/dev/tty", "rb")) == NULL) {
-		(void)fprintf(
-			stderr,
-			"%s: /dev/tty: %s\n",
-			program_name,
-			strerror(errno)
-		);
+		perror(program_name);
 
 		return EX_OSERR;
 	}
 
 	for (;;) {
-		if ( /* prompt and receive */
-			fputs(prompt, stderr) == EOF
-		    || fgets((char *)cmd, (sizeof cmd) / (sizeof *cmd), t) == NULL
-		) { return ioerr(program_name); }
+		if (fputs(prompt, stderr) == EOF) { return ioerr(program_name); }
 
-		if (strchr((char *)cmd, '\n') == NULL) { /* fast-forward stream */
-			int c;
+		// if the line...
+		if (fgets((char *)cmd, (sizeof cmd) / (sizeof *cmd), t) != NULL) {
+			if (strchr((char *)cmd, '\n') == NULL) { // was taken incompletely
+				int c;
 
-			while ((c = fgetc(t)) != '\n') {
-				if (c == EOF) { break; }
+				while ((c = fgetc(t)) != '\n') { // ...fast-forward stream
+					if (c == EOF) { break; }
+				}
 			}
-		}
+		} else { fputc('\n', stdout); } // EOF at start of line; finish prompt
 
 		if (feof(t)) { return EX_OK; }