metablock_iterator: return bool instead of int

This commit changes the return type of sqsh__metablock_iterator_next()
from int to bool. The return value is now used to indicate whether
there is more data to read from the metablock iterator. The error code
is now stored in a pointer to an int instead of being returned directly.

include/sqsh_metablock_private.h

@@ -82,11 +82,15 @@ SQSH_NO_EXPORT SQSH_NO_UNUSED int sqsh__metablock_iterator_init(
  * @memberof SqshMetablockIterator
  * @brief Moves the iterator to the next metablock.
  *
- * @param[in,out] iterator The iterator to advance.
- * @return 0 on success, or a negative value on error.
+ * @param[in,out] iterator  The iterator to advance.
+ * @param[out]    err       Pointer to an int where the error code will be
+ * stored.
+ *
+ * @retval true  If the iterator was moved to the next metablock
+ * @retval false If an error occured. See err for details.
  */
-SQSH_NO_EXPORT SQSH_NO_UNUSED int
-sqsh__metablock_iterator_next(struct SqshMetablockIterator *iterator);
+SQSH_NO_EXPORT bool
+sqsh__metablock_iterator_next(struct SqshMetablockIterator *iterator, int *err);
 
 /**
  * @internal

lib/archive/compression_options.c

@@ -83,7 +83,7 @@ sqsh__compression_options_init(
 		goto out;
 	}
 
-	rv = sqsh__metablock_iterator_next(&context->metablock);
+	sqsh__metablock_iterator_next(&context->metablock, &rv);
 	if (rv < 0) {
 		goto out;
 	}

lib/metablock/metablock_iterator.c

@@ -67,8 +67,9 @@ sqsh__metablock_iterator_init(
 	return rv;
 }
 
-int
-sqsh__metablock_iterator_next(struct SqshMetablockIterator *iterator) {
+bool
+sqsh__metablock_iterator_next(
+		struct SqshMetablockIterator *iterator, int *err) {
 	int rv = 0;
 
 	sqsh__extract_view_cleanup(&iterator->extract_view);
@@ -114,9 +115,16 @@ sqsh__metablock_iterator_next(struct SqshMetablockIterator *iterator) {
 		iterator->data = sqsh__map_reader_data(&iterator->reader);
 		iterator->inner_size = iterator->outer_size;
 	}
-	rv = sqsh__metablock_iterator_size(iterator);
+
+	rv = 0;
 out:
-	return rv;
+	if (err != NULL) {
+		*err = rv;
+	}
+	/* metablock iterators have no way to see if there is a next block. this
+	 * needs to be by the caller.
+	 */
+	return rv == 0;
 }
 
 const uint8_t *

lib/metablock/metablock_reader.c

@@ -43,9 +43,7 @@
 static bool
 metablock_iterator_next(void *iterator, size_t desired_size, int *err) {
 	(void)desired_size;
-	int rv = sqsh__metablock_iterator_next(iterator);
-	*err = rv;
-	return rv > 0;
+	return sqsh__metablock_iterator_next(iterator, err);
 }
 static const uint8_t *
 metablock_iterator_data(const void *iterator) {

test/metablock/metablock_iterator.c

@@ -55,8 +55,10 @@ next_once(void) {
 			&iter, &sqsh, SQSH_SIZEOF_SUPERBLOCK, sizeof(payload));
 	assert(rv == 0);
 
-	rv = sqsh__metablock_iterator_next(&iter);
-	assert(rv == 4);
+	bool has_next = sqsh__metablock_iterator_next(&iter, &rv);
+	assert(rv == 0);
+	assert(has_next);
+
 
 	assert(sqsh__metablock_iterator_size(&iter) == 4);
 
@@ -84,8 +86,9 @@ next_failing_with_no_compression(void) {
 			&iter, &sqsh, SQSH_SIZEOF_SUPERBLOCK, sizeof(payload));
 	assert(rv == 0);
 
-	rv = sqsh__metablock_iterator_next(&iter);
+	bool has_next = sqsh__metablock_iterator_next(&iter, &rv);
 	assert(rv != 0);
+	assert(!has_next);
 
 	rv = sqsh__metablock_iterator_cleanup(&iter);
 	assert(rv == 0);
@@ -114,17 +117,19 @@ next_twice(void) {
 			&iter, &sqsh, SQSH_SIZEOF_SUPERBLOCK, sizeof(payload));
 	assert(rv == 0);
 
-	rv = sqsh__metablock_iterator_next(&iter);
-	assert(rv == 4);
+	bool has_next = sqsh__metablock_iterator_next(&iter, &rv);
+	assert(rv == 0);
+	assert(has_next);
 
 	assert(sqsh__metablock_iterator_size(&iter) == 4);
 
 	p = sqsh__metablock_iterator_data(&iter);
 	assert(p != NULL);
 	assert(memcmp(p, "abcd", 4) == 0);
 
-	rv = sqsh__metablock_iterator_next(&iter);
-	assert(rv == 4);
+	has_next = sqsh__metablock_iterator_next(&iter, &rv);
+	assert(rv == 0);
+	assert(has_next);
 
 	assert(sqsh__metablock_iterator_size(&iter) == 4);
 
@@ -156,17 +161,19 @@ next_compressed(void) {
 			&iter, &sqsh, SQSH_SIZEOF_SUPERBLOCK, sizeof(payload));
 	assert(rv == 0);
 
-	rv = sqsh__metablock_iterator_next(&iter);
-	assert(rv == 4);
+	bool has_next = sqsh__metablock_iterator_next(&iter, &rv);
+	assert(rv == 0);
+	assert(has_next);
 
 	assert(sqsh__metablock_iterator_size(&iter) == 4);
 
 	p = sqsh__metablock_iterator_data(&iter);
 	assert(p != NULL);
 	assert(memcmp(p, "abcd", 4) == 0);
 
-	rv = sqsh__metablock_iterator_next(&iter);
-	assert(rv == 4);
+	has_next = sqsh__metablock_iterator_next(&iter, &rv);
+	assert(rv == 0);
+	assert(has_next);
 
 	assert(sqsh__metablock_iterator_size(&iter) == 4);