bfstd: Expose xmbrtowc() and use it in eval_status()

3 files changed, 46 insertions, 38 deletions

diff --git a/src/bfstd.c b/src/bfstd.c
index cdc33f1..a5a7e54 100644
--- a/src/bfstd.c
+++ b/src/bfstd.c
@@ -586,18 +586,18 @@ int xstrtofflags(const char **str, unsigned long long *set, unsigned long long *
 #endif
 }
 
-/** mbrtowc() wrapper. */
-static int xmbrtowc(wchar_t *wc, size_t *i, const char *str, size_t len, mbstate_t *mb) {
-	size_t mblen = mbrtowc(wc, str + *i, len - *i, mb);
+wint_t xmbrtowc(const char *str, size_t *i, size_t len, mbstate_t *mb) {
+	wchar_t wc;
+	size_t mblen = mbrtowc(&wc, str + *i, len - *i, mb);
 	switch (mblen) {
 	case -1: // Invalid byte sequence
 	case -2: // Incomplete byte sequence
 		*i += 1;
 		memset(mb, 0, sizeof(*mb));
-		return -1;
+		return WEOF;
 	default:
 		*i += mblen;
-		return 0;
+		return wc;
 	}
 }
 
@@ -609,12 +609,12 @@ size_t xstrwidth(const char *str) {
 	memset(&mb, 0, sizeof(mb));
 
 	for (size_t i = 0; i < len;) {
-		wchar_t wc;
-		if (xmbrtowc(&wc, &i, str, len, &mb) == 0) {
-			ret += wcwidth(wc);
-		} else {
+		wint_t wc = xmbrtowc(str, &i, len, &mb);
+		if (wc == WEOF) {
 			// Assume a single-width '?'
 			++ret;
+		} else {
+			ret += wcwidth(wc);
 		}
 	}
 
@@ -729,8 +729,8 @@ multibyte:
 	memset(&mb, 0, sizeof(mb));
 
 	for (size_t j = i; i < len; i = j) {
-		wchar_t wc;
-		if (xmbrtowc(&wc, &j, str, len, &mb) != 0) {
+		wint_t wc = xmbrtowc(str, &j, len, &mb);
+		if (wc == WEOF) {
 			break;
 		}
 		if (!xiswprint(wc, flags)) {
@@ -781,8 +781,8 @@ static char *dollar_quote(char *dest, char *end, const char *str, size_t len, en
 		size_t start = i;
 		bool safe = false;
 
-		wchar_t wc;
-		if (xmbrtowc(&wc, &i, str, len, &mb) == 0) {
+		wint_t wc = xmbrtowc(str, &i, len, &mb);
+		if (wc != WEOF) {
 			safe = xiswprint(wc, flags);
 		}
 
diff --git a/src/bfstd.h b/src/bfstd.h
index abde24e..db558c6 100644
--- a/src/bfstd.h
+++ b/src/bfstd.h
@@ -316,7 +316,24 @@ char *xconfstr(int name);
  */
 int xstrtofflags(const char **str, unsigned long long *set, unsigned long long *clear);
 
-// #include <wchar.h>
+#include <wchar.h>
+
+/**
+ * Error-recovering mbrtowc() wrapper.
+ *
+ * @param str
+ *         The string to convert.
+ * @param i
+ *         The current index.
+ * @param len
+ *         The length of the string.
+ * @param mb
+ *         The multi-byte decoding state.
+ * @return
+ *         The wide character at index *i, or WEOF if decoding fails.  In either
+ *         case, *i will be advanced to the next multi-byte character.
+ */
+wint_t xmbrtowc(const char *str, size_t *i, size_t len, mbstate_t *mb);
 
 /**
  * wcswidth() variant that works on narrow strings.
diff --git a/src/eval.c b/src/eval.c
index 3d396fa..6230353 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -1114,6 +1114,7 @@ static void eval_status(struct bfs_eval *state, struct bfs_bar *bar, struct time
 
 	const struct BFTW *ftwbuf = state->ftwbuf;
 
+	dchar *status = NULL;
 	dchar *rhs = dstrprintf(" (visited: %zu, depth: %2zu)", count, ftwbuf->depth);
 	if (!rhs) {
 		return;
@@ -1125,9 +1126,9 @@ static void eval_status(struct bfs_eval *state, struct bfs_bar *bar, struct time
 		rhslen = 0;
 	}
 
-	dchar *status = dstralloc(0);
+	status = dstralloc(0);
 	if (!status) {
-		goto out_rhs;
+		goto out;
 	}
 
 	const char *path = ftwbuf->path;
@@ -1139,20 +1140,14 @@ static void eval_status(struct bfs_eval *state, struct bfs_bar *bar, struct time
 	// Try to make sure even wide characters fit in the status bar
 	size_t pathmax = width - rhslen - 3;
 	size_t pathwidth = 0;
+	size_t lhslen = 0;
 	mbstate_t mb;
 	memset(&mb, 0, sizeof(mb));
-	while (pathlen > 0) {
-		wchar_t wc;
-		size_t len = mbrtowc(&wc, path, pathlen, &mb);
+	for (size_t i = lhslen; lhslen < pathlen; lhslen = i) {
+		wint_t wc = xmbrtowc(path, &i, pathlen, &mb);
 		int cwidth;
-		if (len == (size_t)-1) {
+		if (wc == WEOF) {
 			// Invalid byte sequence, assume a single-width '?'
-			len = 1;
-			cwidth = 1;
-			memset(&mb, 0, sizeof(mb));
-		} else if (len == (size_t)-2) {
-			// Incomplete byte sequence, assume a single-width '?'
-			len = pathlen;
 			cwidth = 1;
 		} else {
 			cwidth = wcwidth(wc);
@@ -1164,35 +1159,31 @@ static void eval_status(struct bfs_eval *state, struct bfs_bar *bar, struct time
 		if (pathwidth + cwidth > pathmax) {
 			break;
 		}
-
-		if (dstrncat(&status, path, len) != 0) {
-			goto out_rhs;
-		}
-
-		path += len;
-		pathlen -= len;
 		pathwidth += cwidth;
 	}
 
+	if (dstrncat(&status, path, lhslen) != 0) {
+		goto out;
+	}
 	if (dstrcat(&status, "...") != 0) {
-		goto out_rhs;
+		goto out;
 	}
 
 	while (pathwidth < pathmax) {
 		if (dstrapp(&status, ' ') != 0) {
-			goto out_rhs;
+			goto out;
 		}
 		++pathwidth;
 	}
 
-	if (dstrcat(&status, rhs) != 0) {
-		goto out_rhs;
+	if (dstrdcat(&status, rhs) != 0) {
+		goto out;
 	}
 
 	bfs_bar_update(bar, status);
 
+out:
 	dstrfree(status);
-out_rhs:
 	dstrfree(rhs);
 }