runtime: format: add truncation and single-line support to value_writer

bshell.runtime/format/value-writer.c

@@ -15,17 +15,22 @@ static void initialise_table(
 	w->w_table_initialised = true;
 }
 
-static void write_iterable(struct bshell_value_writer *w, const fx_value *value)
+static size_t write_iterable(
+	struct bshell_value_writer *w,
+	const fx_value *value)
 {
+	size_t written = 0;
 	fx_array *array = NULL;
 	fx_value_get_object(value, &array);
 
 	const fx_iterator *it = fx_iterator_begin(array);
 	fx_foreach(v, it)
 	{
-		bshell_value_writer_write(w, v);
+		written += bshell_value_writer_write(w, v);
 	}
 	fx_iterator_unref(it);
+
+	return written;
 }
 
 static bool string_has_trailing_newline(const char *s)
@@ -38,34 +43,105 @@ static bool string_has_trailing_newline(const char *s)
 	return s[len - 1] == '\n';
 }
 
-static void write_string(struct bshell_value_writer *w, const fx_value *value)
+static size_t write_control_char(struct bshell_value_writer *w, fx_wchar c)
 {
-	const char *str = NULL;
-	fx_value_get_cstr(value, &str);
-	fx_stream_write_cstr(w->w_dest, str, NULL);
+	bool oneline = (w->w_flags & BSHELL_VALUE_WRITER_ONELINE) != 0;
+	size_t written = 1;
 
-	if (!string_has_trailing_newline(str)) {
-		fx_stream_write_char(w->w_dest, '\n');
+	switch (c) {
+	case '\n':
+		if (oneline) {
+			fx_stream_write_cstr(w->w_dest, "\\n", &written);
+		} else {
+			fx_stream_write_char(w->w_dest, '\n');
+		}
+		break;
+	case '\r':
+		fx_stream_write_cstr(w->w_dest, "\\r", NULL);
+		break;
+	case '\t':
+		fx_stream_write_cstr(w->w_dest, "\\t", NULL);
+		break;
+	case '\b':
+		fx_stream_write_cstr(w->w_dest, "\\b", NULL);
+		break;
+	default:
+		written = 0;
+		break;
 	}
+
+	return written;
 }
 
-static void write_value(struct bshell_value_writer *w, const fx_value *value)
+static size_t write_string(struct bshell_value_writer *w, const fx_value *value)
+{
+	const char *s = NULL;
+	size_t written = 0;
+	fx_value_get_cstr(value, &s);
+	bool trailing_newline = string_has_trailing_newline(s);
+	bool inhibit_newline
+		= (w->w_flags & BSHELL_VALUE_WRITER_NO_NEWLINE) != 0;
+	bool truncate = (w->w_flags & BSHELL_VALUE_WRITER_TRUNCATE) != 0;
+
+	for (written = 0; *s;) {
+		if (truncate && written == w->w_max_width - 1) {
+			fx_stream_write_char(w->w_dest, L'…');
+			written++;
+			break;
+		}
+
+		fx_wchar c = fx_wchar_utf8_codepoint_decode(s);
+		unsigned int stride = fx_wchar_utf8_codepoint_size(c);
+		if (stride == 0) {
+			break;
+		}
+
+		if (!fx_wchar_is_graph(c)) {
+			written += write_control_char(w, c);
+			goto next;
+		}
+
+		char cs[5] = {0};
+		fx_wchar_utf8_codepoint_encode(c, cs);
+
+		size_t n = 0;
+		fx_stream_write_cstr(w->w_dest, cs, &n);
+		written += n;
+
+	next:
+		s += stride;
+	}
+
+	if (!trailing_newline && !inhibit_newline) {
+		fx_stream_write_char(w->w_dest, '\n');
+		written++;
+	}
+
+	return written;
+}
+
+static size_t write_value(struct bshell_value_writer *w, const fx_value *value)
 {
 	const fx_type *ty = fx_type_get_by_id(value->v_type);
-	if (fx_value_is_type(value, FX_TYPE_STRING)) {
-		write_string(w, value);
-		return;
+	if (fx_value_is_type(value, FX_TYPE_STRING)
+	    || fx_value_is_type(value, FX_TYPE_CSTR)) {
+		return write_string(w, value);
 	}
 
 	if (fx_type_get_interface(ty, FX_TYPE_ITERABLE)) {
-		write_iterable(w, value);
-		return;
+		return write_iterable(w, value);
 	}
 
 	if (fx_type_is_value_type(value->v_type)) {
-		fx_value_to_string(value, w->w_dest, NULL);
-		fx_stream_write_char(w->w_dest, '\n');
-		return;
+		fx_stringstream_reset(w->w_tmp);
+		fx_value_to_string(value, w->w_tmp, NULL);
+		fx_stream_write_char(w->w_tmp, '\n');
+		size_t result = fx_stringstream_get_length(w->w_tmp);
+		fx_stream_write_cstr(
+			w->w_dest,
+			fx_stringstream_get_cstr(w->w_tmp),
+			NULL);
+		return result;
 	}
 
 	if (!w->w_table_initialised) {
@@ -73,19 +149,27 @@ static void write_value(struct bshell_value_writer *w, const fx_value *value)
 	}
 
 	bshell_table_ctx_print_record(&w->w_table_ctx, value);
+	return 0;
 }
 
-void bshell_value_writer_init(struct bshell_value_writer *w, fx_stream *dest)
+void bshell_value_writer_init(
+	struct bshell_value_writer *w,
+	enum bshell_value_writer_flags flags,
+	size_t max_width,
+	fx_stream *dest)
 {
 	memset(w, 0x00, sizeof *w);
 	w->w_dest = dest;
+	w->w_flags = flags;
+	w->w_max_width = max_width;
+	w->w_tmp = fx_stringstream_create();
 }
 
-void bshell_value_writer_write(
+size_t bshell_value_writer_write(
 	struct bshell_value_writer *w,
 	const fx_value *value)
 {
-	write_value(w, value);
+	return write_value(w, value);
 }
 
 void bshell_value_writer_cleanup(struct bshell_value_writer *w)
@@ -94,5 +178,7 @@ void bshell_value_writer_cleanup(struct bshell_value_writer *w)
 		bshell_table_ctx_cleanup(&w->w_table_ctx);
 	}
 
+	fx_stringstream_unref(w->w_tmp);
+
 	w->w_table_initialised = false;
 }