1 files changed, 302 insertions, 0 deletions
diff --git a/reftable/iter.c b/reftable/iter.c
new file mode 100644
index 0000000000..2ecc52b336
--- /dev/null
+++ b/reftable/iter.c
@@ -0,0 +1,302 @@
+/*
+ * Copyright 2020 Google LLC
+ *
+ * Use of this source code is governed by a BSD-style
+ * license that can be found in the LICENSE file or at
+ * https://developers.google.com/open-source/licenses/bsd
+ */
+
+#include "iter.h"
+
+#include "system.h"
+
+#include "block.h"
+#include "blocksource.h"
+#include "constants.h"
+#include "reftable-error.h"
+#include "table.h"
+
+int iterator_seek(struct reftable_iterator *it, struct reftable_record *want)
+{
+	return it->ops->seek(it->iter_arg, want);
+}
+
+int iterator_next(struct reftable_iterator *it, struct reftable_record *rec)
+{
+	return it->ops->next(it->iter_arg, rec);
+}
+
+static int empty_iterator_seek(void *arg REFTABLE_UNUSED, struct reftable_record *want REFTABLE_UNUSED)
+{
+	return 0;
+}
+
+static int empty_iterator_next(void *arg REFTABLE_UNUSED, struct reftable_record *rec REFTABLE_UNUSED)
+{
+	return 1;
+}
+
+static void empty_iterator_close(void *arg REFTABLE_UNUSED)
+{
+}
+
+static struct reftable_iterator_vtable empty_vtable = {
+	.seek = &empty_iterator_seek,
+	.next = &empty_iterator_next,
+	.close = &empty_iterator_close,
+};
+
+void iterator_set_empty(struct reftable_iterator *it)
+{
+	assert(!it->ops);
+	it->iter_arg = NULL;
+	it->ops = &empty_vtable;
+}
+
+static void filtering_ref_iterator_close(void *iter_arg)
+{
+	struct filtering_ref_iterator *fri = iter_arg;
+	reftable_buf_release(&fri->oid);
+	reftable_iterator_destroy(&fri->it);
+}
+
+static int filtering_ref_iterator_seek(void *iter_arg,
+				       struct reftable_record *want)
+{
+	struct filtering_ref_iterator *fri = iter_arg;
+	return iterator_seek(&fri->it, want);
+}
+
+static int filtering_ref_iterator_next(void *iter_arg,
+				       struct reftable_record *rec)
+{
+	struct filtering_ref_iterator *fri = iter_arg;
+	struct reftable_ref_record *ref = &rec->u.ref;
+	int err = 0;
+	while (1) {
+		err = reftable_iterator_next_ref(&fri->it, ref);
+		if (err != 0) {
+			break;
+		}
+
+		if (ref->value_type == REFTABLE_REF_VAL2 &&
+		    (!memcmp(fri->oid.buf, ref->value.val2.target_value,
+			     fri->oid.len) ||
+		     !memcmp(fri->oid.buf, ref->value.val2.value,
+			     fri->oid.len)))
+			return 0;
+
+		if (ref->value_type == REFTABLE_REF_VAL1 &&
+		    !memcmp(fri->oid.buf, ref->value.val1, fri->oid.len)) {
+			return 0;
+		}
+	}
+
+	reftable_ref_record_release(ref);
+	return err;
+}
+
+static struct reftable_iterator_vtable filtering_ref_iterator_vtable = {
+	.seek = &filtering_ref_iterator_seek,
+	.next = &filtering_ref_iterator_next,
+	.close = &filtering_ref_iterator_close,
+};
+
+void iterator_from_filtering_ref_iterator(struct reftable_iterator *it,
+					  struct filtering_ref_iterator *fri)
+{
+	assert(!it->ops);
+	it->iter_arg = fri;
+	it->ops = &filtering_ref_iterator_vtable;
+}
+
+static void indexed_table_ref_iter_close(void *p)
+{
+	struct indexed_table_ref_iter *it = p;
+	block_iter_close(&it->cur);
+	block_source_release_data(&it->block.block_data);
+	reftable_free(it->offsets);
+	reftable_buf_release(&it->oid);
+}
+
+static int indexed_table_ref_iter_next_block(struct indexed_table_ref_iter *it)
+{
+	uint64_t off;
+	int err = 0;
+	if (it->offset_idx == it->offset_len) {
+		it->is_finished = 1;
+		return 1;
+	}
+
+	block_source_release_data(&it->block.block_data);
+
+	off = it->offsets[it->offset_idx++];
+	err = table_init_block(it->table, &it->block, off, REFTABLE_BLOCK_TYPE_REF);
+	if (err < 0) {
+		return err;
+	}
+	if (err > 0) {
+		/* indexed block does not exist. */
+		return REFTABLE_FORMAT_ERROR;
+	}
+	block_iter_init(&it->cur, &it->block);
+	return 0;
+}
+
+static int indexed_table_ref_iter_seek(void *p REFTABLE_UNUSED,
+				       struct reftable_record *want REFTABLE_UNUSED)
+{
+	return REFTABLE_API_ERROR;
+}
+
+static int indexed_table_ref_iter_next(void *p, struct reftable_record *rec)
+{
+	struct indexed_table_ref_iter *it = p;
+	struct reftable_ref_record *ref = &rec->u.ref;
+
+	while (1) {
+		int err = block_iter_next(&it->cur, rec);
+		if (err < 0) {
+			return err;
+		}
+
+		if (err > 0) {
+			err = indexed_table_ref_iter_next_block(it);
+			if (err < 0) {
+				return err;
+			}
+
+			if (it->is_finished) {
+				return 1;
+			}
+			continue;
+		}
+		/* BUG */
+		if (!memcmp(it->oid.buf, ref->value.val2.target_value,
+			    it->oid.len) ||
+		    !memcmp(it->oid.buf, ref->value.val2.value, it->oid.len)) {
+			return 0;
+		}
+	}
+}
+
+int indexed_table_ref_iter_new(struct indexed_table_ref_iter **dest,
+			       struct reftable_table *t, uint8_t *oid,
+			       int oid_len, uint64_t *offsets, int offset_len)
+{
+	struct indexed_table_ref_iter empty = INDEXED_TABLE_REF_ITER_INIT;
+	struct indexed_table_ref_iter *itr;
+	int err = 0;
+
+	itr = reftable_calloc(1, sizeof(*itr));
+	if (!itr) {
+		err = REFTABLE_OUT_OF_MEMORY_ERROR;
+		goto out;
+	}
+
+	*itr = empty;
+	itr->table = t;
+
+	err = reftable_buf_add(&itr->oid, oid, oid_len);
+	if (err < 0)
+		goto out;
+
+	itr->offsets = offsets;
+	itr->offset_len = offset_len;
+
+	err = indexed_table_ref_iter_next_block(itr);
+	if (err < 0)
+		goto out;
+
+	*dest = itr;
+	err = 0;
+
+out:
+	if (err < 0) {
+		*dest = NULL;
+		reftable_free(itr);
+	}
+	return err;
+}
+
+static struct reftable_iterator_vtable indexed_table_ref_iter_vtable = {
+	.seek = &indexed_table_ref_iter_seek,
+	.next = &indexed_table_ref_iter_next,
+	.close = &indexed_table_ref_iter_close,
+};
+
+void iterator_from_indexed_table_ref_iter(struct reftable_iterator *it,
+					  struct indexed_table_ref_iter *itr)
+{
+	assert(!it->ops);
+	it->iter_arg = itr;
+	it->ops = &indexed_table_ref_iter_vtable;
+}
+
+void reftable_iterator_destroy(struct reftable_iterator *it)
+{
+	if (!it->ops)
+		return;
+	it->ops->close(it->iter_arg);
+	it->ops = NULL;
+	REFTABLE_FREE_AND_NULL(it->iter_arg);
+}
+
+int reftable_iterator_seek_ref(struct reftable_iterator *it,
+			       const char *name)
+{
+	struct reftable_record want = {
+		.type = REFTABLE_BLOCK_TYPE_REF,
+		.u.ref = {
+			.refname = (char *)name,
+		},
+	};
+	return it->ops->seek(it->iter_arg, &want);
+}
+
+int reftable_iterator_next_ref(struct reftable_iterator *it,
+			       struct reftable_ref_record *ref)
+{
+	struct reftable_record rec = {
+		.type = REFTABLE_BLOCK_TYPE_REF,
+		.u = {
+			.ref = *ref
+		},
+	};
+	int err = iterator_next(it, &rec);
+	*ref = rec.u.ref;
+	return err;
+}
+
+int reftable_iterator_seek_log_at(struct reftable_iterator *it,
+				  const char *name, uint64_t update_index)
+{
+	struct reftable_record want = {
+		.type = REFTABLE_BLOCK_TYPE_LOG,
+		.u.log = {
+			.refname = (char *)name,
+			.update_index = update_index,
+		},
+	};
+	return it->ops->seek(it->iter_arg, &want);
+}
+
+int reftable_iterator_seek_log(struct reftable_iterator *it,
+			       const char *name)
+{
+	return reftable_iterator_seek_log_at(it, name, ~((uint64_t) 0));
+}
+
+int reftable_iterator_next_log(struct reftable_iterator *it,
+			       struct reftable_log_record *log)
+{
+	struct reftable_record rec = {
+		.type = REFTABLE_BLOCK_TYPE_LOG,
+		.u = {
+			.log = *log,
+		},
+	};
+	int err = iterator_next(it, &rec);
+	*log = rec.u.log;
+	return err;
+}