global: Use buffer_get_writable_size() where possible

With 09539f3 increasing buffer's init_size with +1 some fts-icu unit tests
started failing. And in general it's better to use the writable size since
that provides the true size that can be used.

src/lib-fts/test-fts-icu.c

@@ -11,18 +11,17 @@
 
 static void test_fts_icu_utf8_to_utf16_ascii_resize(void)
 {
-	buffer_t *dest = buffer_create_dynamic(pool_datastack_create(), 5);
+	buffer_t *dest = buffer_create_dynamic(pool_datastack_create(), 4);
 
 	test_begin("fts_icu_utf8_to_utf16 ascii resize");
-	/* dynamic buffers reserve +1 for str_c()'s NUL, so 5 -> 4 */
-	test_assert(buffer_get_size(dest) == 5);
+	test_assert(buffer_get_writable_size(dest) == 4);
 	fts_icu_utf8_to_utf16(dest, "12");
 	test_assert(dest->used == 4);
-	test_assert(buffer_get_size(dest) == 5);
+	test_assert(buffer_get_writable_size(dest) == 4);
 
 	fts_icu_utf8_to_utf16(dest, "123");
 	test_assert(dest->used == 6);
-	test_assert(buffer_get_size(dest) == 8);
+	test_assert(buffer_get_writable_size(dest) == 7);
 
 	fts_icu_utf8_to_utf16(dest, "12345");
 	test_assert(dest->used == 10);
@@ -38,7 +37,7 @@ static void test_fts_icu_utf8_to_utf16_32bit_resize(void)
 	test_begin("fts_icu_utf8_to_utf16 32bit resize");
 	for (i = 2; i <= 5; i++) {
 		dest = buffer_create_dynamic(pool_datastack_create(), i);
-		test_assert(buffer_get_size(dest) == i);
+		test_assert(buffer_get_writable_size(dest) == i);
 		fts_icu_utf8_to_utf16(dest, "\xF0\x90\x90\x80"); /* 0x10400 */
 		test_assert(dest->used == 4);
 	}
@@ -69,7 +68,7 @@ static void test_fts_icu_utf16_to_utf8_resize(void)
 	test_begin("fts_icu_utf16_to_utf8 resize");
 	for (i = 2; i <= 6; i++) {
 		dest = t_str_new(i);
-		test_assert(buffer_get_size(dest) == i);
+		test_assert(buffer_get_writable_size(dest) == i);
 		fts_icu_utf16_to_utf8(dest, &src, 1);
 		test_assert(dest->used == 3);
 		test_assert(strcmp(str_c(dest), UNICODE_REPLACEMENT_CHAR_UTF8) == 0);
@@ -131,7 +130,7 @@ static void test_fts_icu_translate_resize(void)
 		buffer_set_used_size(src_utf16, 0);
 		fts_icu_utf8_to_utf16(src_utf16, src_utf8);
 		dest = buffer_create_dynamic(pool_datastack_create(), i);
-		test_assert(buffer_get_size(dest) == i);
+		test_assert(buffer_get_writable_size(dest) == i);
 		test_assert(fts_icu_translate(dest, src_utf16->data,
 					      src_utf16->used/sizeof(UChar),
 					      translit, &error) == 0);
@@ -159,12 +158,12 @@ static void test_fts_icu_lcase_resize(void)
 	unsigned int i;
 
 	test_begin("fts_icu_lcase resize");
-	for (i = 2; i <= 4; i++) {
+	for (i = 1; i <= 3; i++) {
 		dest = t_str_new(i);
-		test_assert(buffer_get_size(dest) == i);
+		test_assert(buffer_get_writable_size(dest) == i);
 		fts_icu_lcase(dest, src);
 		test_assert(strcmp(str_c(dest), "a\xC3\xA4") == 0);
-		test_assert(buffer_get_size(dest) == 4);
+		test_assert(buffer_get_writable_size(dest) == 3);
 	}
 
 	test_end();

src/lib-ssl-iostream/ostream-openssl.c

@@ -50,7 +50,7 @@ o_stream_ssl_buffer(struct ssl_ostream *sstream, const struct const_iovec *iov,
 	if (sstream->ostream.max_buffer_size == 0) {
 		/* we're requeted to use whatever space is available in
 		   the buffer */
-		avail = buffer_get_size(sstream->buffer) - sstream->buffer->used;
+		avail = buffer_get_writable_size(sstream->buffer) - sstream->buffer->used;
 	} else {
 		avail = sstream->ostream.max_buffer_size > sstream->buffer->used ?
 			sstream->ostream.max_buffer_size - sstream->buffer->used : 0;

src/lib/aqueue.c

@@ -10,7 +10,7 @@ struct aqueue *aqueue_init(struct array *array)
 
 	aqueue = i_new(struct aqueue, 1);
 	aqueue->arr = array;
-	aqueue->area_size = buffer_get_size(aqueue->arr->buffer) /
+	aqueue->area_size = buffer_get_writable_size(aqueue->arr->buffer) /
 		aqueue->arr->element_size;
 	i_assert(aqueue->area_size > 0);
 	return aqueue;
@@ -32,7 +32,7 @@ static void aqueue_grow(struct aqueue *aqueue)
 
 	orig_area_size = aqueue->area_size;
 	(void)array_append_space_i(aqueue->arr);
-	aqueue->area_size = buffer_get_size(aqueue->arr->buffer) /
+	aqueue->area_size = buffer_get_writable_size(aqueue->arr->buffer) /
 		aqueue->arr->element_size;
 	i_assert(orig_area_size < aqueue->area_size);
 

src/lib/str.c

@@ -153,11 +153,11 @@ void str_vprintfa(string_t *str, const char *fmt, va_list args)
 	init_size += SNPRINTF_INITIAL_EXTRA_SIZE;
 
 	/* @UNSAFE */
-	if (pos+init_size > buffer_get_size(str) &&
-	    pos < buffer_get_size(str)) {
+	if (pos+init_size > buffer_get_writable_size(str) &&
+	    pos < buffer_get_writable_size(str)) {
 		/* avoid growing buffer larger if possible. this is also
 		   required if buffer isn't dynamically growing. */
-		init_size = buffer_get_size(str)-pos;
+		init_size = buffer_get_writable_size(str)-pos;
 	}
 	tmp = buffer_get_space_unsafe(str, pos, init_size);
 	ret = vsnprintf(tmp, init_size, fmt, args);