bfstd: New wrappers for dirname()/basename()

9 files changed, 84 insertions, 27 deletions

diff --git a/src/bfstd.c b/src/bfstd.c
index 1561796..3a37250 100644
--- a/src/bfstd.c
+++ b/src/bfstd.c
@@ -45,17 +45,52 @@ bool is_nonexistence_error(int error) {
 	return error == ENOENT || errno == ENOTDIR;
 }
 
-const char *xbasename(const char *path) {
-	const char *i;
+char *xdirname(const char *path) {
+	size_t i = xbaseoff(path);
 
 	// Skip trailing slashes
-	for (i = path + strlen(path); i > path && i[-1] == '/'; --i);
+	while (i > 0 && path[i - 1] == '/') {
+		--i;
+	}
+
+	if (i > 0) {
+		return strndup(path, i);
+	} else if (path[i] == '/') {
+		return strdup("/");
+	} else {
+		return strdup(".");
+	}
+}
+
+char *xbasename(const char *path) {
+	size_t i = xbaseoff(path);
+	size_t len = strcspn(path + i, "/");
+	if (len > 0) {
+		return strndup(path + i, len);
+	} else if (path[i] == '/') {
+		return strdup("/");
+	} else {
+		return strdup(".");
+	}
+}
+
+size_t xbaseoff(const char *path) {
+	size_t i = strlen(path);
+
+	// Skip trailing slashes
+	while (i > 0 && path[i - 1] == '/') {
+		--i;
+	}
 
 	// Find the beginning of the name
-	for (; i > path && i[-1] != '/'; --i);
+	while (i > 0 && path[i - 1] != '/') {
+		--i;
+	}
 
 	// Skip leading slashes
-	for (; i[0] == '/' && i[1]; ++i);
+	while (path[i] == '/' && path[i + 1]) {
+		++i;
+	}
 
 	return i;
 }
diff --git a/src/bfstd.h b/src/bfstd.h
index 6bf6ec8..d46fa02 100644
--- a/src/bfstd.h
+++ b/src/bfstd.h
@@ -22,6 +22,7 @@
 #define BFS_BFSTD_H
 
 #include <stdbool.h>
+#include <stddef.h>
 
 // #include <errno.h>
 
@@ -45,13 +46,34 @@ bool is_nonexistence_error(int error);
 // #include <libgen.h>
 
 /**
- * basename() variant that doesn't modify the input.
+ * Re-entrant dirname() variant that always allocates a copy.
  *
  * @param path
  *         The path in question.
- * @return A pointer into path at the base name offset.
+ * @return
+ *         The parent directory of the path.
+ */
+char *xdirname(const char *path);
+
+/**
+ * Re-entrant basename() variant that always allocates a copy.
+ *
+ * @param path
+ *         The path in question.
+ * @return
+ *         The final component of the path.
+ */
+char *xbasename(const char *path);
+
+/**
+ * Find the offset of the final component of a path.
+ *
+ * @param path
+ *         The path in question.
+ * @return
+ *         The offset of the basename.
  */
-const char *xbasename(const char *path);
+size_t xbaseoff(const char *path);
 
 #include <stdio.h>
 
diff --git a/src/bftw.c b/src/bftw.c
index 8c88101..5f3ebde 100644
--- a/src/bftw.c
+++ b/src/bftw.c
@@ -793,7 +793,7 @@ static void bftw_init_ftwbuf(struct bftw_state *state, enum bftw_visit visit) {
 
 	if (ftwbuf->depth == 0) {
 		// Compute the name offset for root paths like "foo/bar"
-		ftwbuf->nameoff = xbasename(ftwbuf->path) - ftwbuf->path;
+		ftwbuf->nameoff = xbaseoff(ftwbuf->path);
 	}
 
 	if (ftwbuf->error != 0) {
diff --git a/src/color.c b/src/color.c
index cc37e96..7c16ec5 100644
--- a/src/color.c
+++ b/src/color.c
@@ -809,7 +809,7 @@ static int print_path_colored(CFILE *cfile, const char *path, const struct BFTW
 	if (path == ftwbuf->path) {
 		nameoff = ftwbuf->nameoff;
 	} else {
-		nameoff = xbasename(path) - path;
+		nameoff = xbaseoff(path);
 	}
 
 	if (print_dirs_colored(cfile, path, ftwbuf, flags, nameoff) != 0) {
diff --git a/src/diag.c b/src/diag.c
index a0c11f2..b02473a 100644
--- a/src/diag.c
+++ b/src/diag.c
@@ -84,13 +84,18 @@ bool bfs_vdebug(const struct bfs_ctx *ctx, enum debug_flags flag, const char *fo
 	}
 }
 
+/** Get the command name without any leading directories. */
+static const char *bfs_cmd(const struct bfs_ctx *ctx) {
+	return ctx->argv[0] + xbaseoff(ctx->argv[0]);
+}
+
 void bfs_error_prefix(const struct bfs_ctx *ctx) {
-	cfprintf(ctx->cerr, "${bld}%s:${rs} ${err}error:${rs} ", xbasename(ctx->argv[0]));
+	cfprintf(ctx->cerr, "${bld}%s:${rs} ${err}error:${rs} ", bfs_cmd(ctx));
 }
 
 bool bfs_warning_prefix(const struct bfs_ctx *ctx) {
 	if (ctx->warn) {
-		cfprintf(ctx->cerr, "${bld}%s:${rs} ${wrn}warning:${rs} ", xbasename(ctx->argv[0]));
+		cfprintf(ctx->cerr, "${bld}%s:${rs} ${wrn}warning:${rs} ", bfs_cmd(ctx));
 		return true;
 	} else {
 		return false;
@@ -99,7 +104,7 @@ bool bfs_warning_prefix(const struct bfs_ctx *ctx) {
 
 bool bfs_debug_prefix(const struct bfs_ctx *ctx, enum debug_flags flag) {
 	if (ctx->debug & flag) {
-		cfprintf(ctx->cerr, "${bld}%s:${rs} ${cyn}-D %s${rs}: ", xbasename(ctx->argv[0]), debug_flag_name(flag));
+		cfprintf(ctx->cerr, "${bld}%s:${rs} ${cyn}-D %s${rs}: ", bfs_cmd(ctx), debug_flag_name(flag));
 		return true;
 	} else {
 		return false;
diff --git a/src/eval.c b/src/eval.c
index 89591b2..32b2e0e 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -590,15 +590,7 @@ bool eval_name(const struct bfs_expr *expr, struct bfs_eval *state) {
 	if (ftwbuf->depth == 0) {
 		// Any trailing slashes are not part of the name.  This can only
 		// happen for the root path.
-		const char *slash = strchr(name, '/');
-		if (slash && slash > name) {
-			copy = strndup(name, slash - name);
-			if (!copy) {
-				eval_report_error(state);
-				return false;
-			}
-			name = copy;
-		}
+		name = copy = xbasename(name);
 	}
 
 	bool ret = fnmatch(expr->argv[1], name, expr->num) == 0;
diff --git a/src/exec.c b/src/exec.c
index a1cbde1..8630469 100644
--- a/src/exec.c
+++ b/src/exec.c
@@ -295,7 +295,7 @@ static int bfs_exec_openwd(struct bfs_exec *execbuf, const struct BFTW *ftwbuf)
 
 	if (ftwbuf->at_fd != AT_FDCWD) {
 		// Rely on at_fd being the immediate parent
-		assert(ftwbuf->at_path == xbasename(ftwbuf->at_path));
+		assert(xbaseoff(ftwbuf->at_path) == 0);
 
 		execbuf->wd_fd = ftwbuf->at_fd;
 		if (!(execbuf->flags & BFS_EXEC_MULTI)) {
diff --git a/src/mtab.c b/src/mtab.c
index 316ec6e..39676e5 100644
--- a/src/mtab.c
+++ b/src/mtab.c
@@ -86,7 +86,8 @@ static int bfs_mtab_add(struct bfs_mtab *mtab, const char *path, const char *typ
 		goto fail_entry;
 	}
 
-	if (!trie_insert_str(&mtab->names, xbasename(path))) {
+	const char *name = path + xbaseoff(path);
+	if (!trie_insert_str(&mtab->names, name)) {
 		goto fail;
 	}
 
@@ -223,7 +224,7 @@ const char *bfs_fstype(const struct bfs_mtab *mtab, const struct bfs_stat *statb
 }
 
 bool bfs_might_be_mount(const struct bfs_mtab *mtab, const char *path) {
-	const char *name = xbasename(path);
+	const char *name = path + xbaseoff(path);
 	return trie_find_str(&mtab->names, name);
 }
 
diff --git a/src/parse.c b/src/parse.c
index ad32714..51a9d0a 100644
--- a/src/parse.c
+++ b/src/parse.c
@@ -2888,7 +2888,8 @@ static CFILE *launch_pager(pid_t *pid, CFILE *cout) {
 		NULL,
 	};
 
-	if (strcmp(xbasename(exe), "less") == 0) {
+	const char *cmd = exe + xbaseoff(exe);
+	if (strcmp(cmd, "less") == 0) {
 		// We know less supports colors, other pagers may not
 		ret->colors = cout->colors;
 		argv[1] = "-FKRX";
@@ -3931,7 +3932,8 @@ struct bfs_ctx *bfs_parse_cmdline(int argc, char *argv[]) {
 		.now = ctx->now,
 	};
 
-	if (strcmp(xbasename(state.command), "find") == 0) {
+	const char *cmd = state.command + xbaseoff(state.command);
+	if (strcmp(cmd, "find") == 0) {
 		// Operate depth-first when invoked as "find"
 		ctx->strategy = BFTW_DFS;
 	}