1 files changed, 154 insertions, 167 deletions

diff --git a/reftable/reader.c b/reftable/reader.c
index 29c99e2269..ea82955c9b 100644
--- a/reftable/reader.c
+++ b/reftable/reader.c
@@ -11,11 +11,9 @@ https://developers.google.com/open-source/licenses/bsd
 #include "system.h"
 #include "block.h"
 #include "constants.h"
-#include "generic.h"
 #include "iter.h"
 #include "record.h"
 #include "reftable-error.h"
-#include "reftable-generic.h"
 
 uint64_t block_source_size(struct reftable_block_source *source)
 {
@@ -69,7 +67,7 @@ static int reader_get_block(struct reftable_reader *r,
 	return block_source_read_block(&r->source, dest, off, sz);
 }
 
-uint32_t reftable_reader_hash_id(struct reftable_reader *r)
+enum reftable_hash reftable_reader_hash_id(struct reftable_reader *r)
 {
 	return r->hash_id;
 }
@@ -109,18 +107,20 @@ static int parse_footer(struct reftable_reader *r, uint8_t *footer,
 	f += 8;
 
 	if (r->version == 1) {
-		r->hash_id = GIT_SHA1_FORMAT_ID;
+		r->hash_id = REFTABLE_HASH_SHA1;
 	} else {
-		r->hash_id = get_be32(f);
-		switch (r->hash_id) {
-		case GIT_SHA1_FORMAT_ID:
+		switch (get_be32(f)) {
+		case REFTABLE_FORMAT_ID_SHA1:
+			r->hash_id = REFTABLE_HASH_SHA1;
 			break;
-		case GIT_SHA256_FORMAT_ID:
+		case REFTABLE_FORMAT_ID_SHA256:
+			r->hash_id = REFTABLE_HASH_SHA256;
 			break;
 		default:
 			err = REFTABLE_FORMAT_ERROR;
 			goto done;
 		}
+
 		f += 4;
 	}
 
@@ -164,58 +164,6 @@ done:
 	return err;
 }
 
-int init_reader(struct reftable_reader *r, struct reftable_block_source *source,
-		const char *name)
-{
-	struct reftable_block footer = { NULL };
-	struct reftable_block header = { NULL };
-	int err = 0;
-	uint64_t file_size = block_source_size(source);
-
-	/* Need +1 to read type of first block. */
-	uint32_t read_size = header_size(2) + 1; /* read v2 because it's larger.  */
-	memset(r, 0, sizeof(struct reftable_reader));
-
-	if (read_size > file_size) {
-		err = REFTABLE_FORMAT_ERROR;
-		goto done;
-	}
-
-	err = block_source_read_block(source, &header, 0, read_size);
-	if (err != read_size) {
-		err = REFTABLE_IO_ERROR;
-		goto done;
-	}
-
-	if (memcmp(header.data, "REFT", 4)) {
-		err = REFTABLE_FORMAT_ERROR;
-		goto done;
-	}
-	r->version = header.data[4];
-	if (r->version != 1 && r->version != 2) {
-		err = REFTABLE_FORMAT_ERROR;
-		goto done;
-	}
-
-	r->size = file_size - footer_size(r->version);
-	r->source = *source;
-	r->name = xstrdup(name);
-	r->hash_id = 0;
-
-	err = block_source_read_block(source, &footer, r->size,
-				      footer_size(r->version));
-	if (err != footer_size(r->version)) {
-		err = REFTABLE_IO_ERROR;
-		goto done;
-	}
-
-	err = parse_footer(r, footer.data, header.data);
-done:
-	reftable_block_done(&footer);
-	reftable_block_done(&header);
-	return err;
-}
-
 struct table_iter {
 	struct reftable_reader *r;
 	uint8_t typ;
@@ -229,6 +177,7 @@ static int table_iter_init(struct table_iter *ti, struct reftable_reader *r)
 {
 	struct block_iter bi = BLOCK_ITER_INIT;
 	memset(ti, 0, sizeof(*ti));
+	reftable_reader_incref(r);
 	ti->r = r;
 	ti->bi = bi;
 	return 0;
@@ -316,6 +265,7 @@ static void table_iter_close(struct table_iter *ti)
 {
 	table_iter_block_done(ti);
 	block_iter_close(&ti->bi);
+	reftable_reader_decref(ti->r);
 }
 
 static int table_iter_next_block(struct table_iter *ti)
@@ -380,6 +330,7 @@ static int table_iter_seek_to(struct table_iter *ti, uint64_t off, uint8_t typ)
 	ti->typ = block_reader_type(&ti->br);
 	ti->block_off = off;
 	block_iter_seek_start(&ti->bi, &ti->br);
+	ti->is_finished = 0;
 	return 0;
 }
 
@@ -401,13 +352,15 @@ static int table_iter_seek_start(struct table_iter *ti, uint8_t typ, int index)
 static int table_iter_seek_linear(struct table_iter *ti,
 				  struct reftable_record *want)
 {
-	struct strbuf want_key = STRBUF_INIT;
-	struct strbuf got_key = STRBUF_INIT;
+	struct reftable_buf want_key = REFTABLE_BUF_INIT;
+	struct reftable_buf got_key = REFTABLE_BUF_INIT;
 	struct reftable_record rec;
 	int err;
 
 	reftable_record_init(&rec, reftable_record_type(want));
-	reftable_record_key(want, &want_key);
+	err = reftable_record_key(want, &want_key);
+	if (err < 0)
+		goto done;
 
 	/*
 	 * First we need to locate the block that must contain our record. To
@@ -452,7 +405,7 @@ static int table_iter_seek_linear(struct table_iter *ti,
 		if (err < 0)
 			goto done;
 
-		if (strbuf_cmp(&got_key, &want_key) > 0) {
+		if (reftable_buf_cmp(&got_key, &want_key) > 0) {
 			table_iter_block_done(&next);
 			break;
 		}
@@ -473,8 +426,8 @@ static int table_iter_seek_linear(struct table_iter *ti,
 
 done:
 	reftable_record_release(&rec);
-	strbuf_release(&want_key);
-	strbuf_release(&got_key);
+	reftable_buf_release(&want_key);
+	reftable_buf_release(&got_key);
 	return err;
 }
 
@@ -482,15 +435,17 @@ static int table_iter_seek_indexed(struct table_iter *ti,
 				   struct reftable_record *rec)
 {
 	struct reftable_record want_index = {
-		.type = BLOCK_TYPE_INDEX, .u.idx = { .last_key = STRBUF_INIT }
+		.type = BLOCK_TYPE_INDEX, .u.idx = { .last_key = REFTABLE_BUF_INIT }
 	};
 	struct reftable_record index_result = {
 		.type = BLOCK_TYPE_INDEX,
-		.u.idx = { .last_key = STRBUF_INIT },
+		.u.idx = { .last_key = REFTABLE_BUF_INIT },
 	};
 	int err;
 
-	reftable_record_key(rec, &want_index.u.idx.last_key);
+	err = reftable_record_key(rec, &want_index.u.idx.last_key);
+	if (err < 0)
+		goto done;
 
 	/*
 	 * The index may consist of multiple levels, where each level may have
@@ -605,59 +560,131 @@ static void iterator_from_table_iter(struct reftable_iterator *it,
 	it->ops = &table_iter_vtable;
 }
 
-static void reader_init_iter(struct reftable_reader *r,
-			     struct reftable_iterator *it,
-			     uint8_t typ)
+int reader_init_iter(struct reftable_reader *r,
+		     struct reftable_iterator *it,
+		     uint8_t typ)
 {
 	struct reftable_reader_offsets *offs = reader_offsets_for(r, typ);
 
 	if (offs->is_present) {
 		struct table_iter *ti;
 		REFTABLE_ALLOC_ARRAY(ti, 1);
+		if (!ti)
+			return REFTABLE_OUT_OF_MEMORY_ERROR;
+
 		table_iter_init(ti, r);
 		iterator_from_table_iter(it, ti);
 	} else {
 		iterator_set_empty(it);
 	}
-}
 
-void reftable_reader_init_ref_iterator(struct reftable_reader *r,
-				       struct reftable_iterator *it)
-{
-	reader_init_iter(r, it, BLOCK_TYPE_REF);
+	return 0;
 }
 
-void reftable_reader_init_log_iterator(struct reftable_reader *r,
-				       struct reftable_iterator *it)
+int reftable_reader_init_ref_iterator(struct reftable_reader *r,
+				      struct reftable_iterator *it)
 {
-	reader_init_iter(r, it, BLOCK_TYPE_LOG);
+	return reader_init_iter(r, it, BLOCK_TYPE_REF);
 }
 
-void reader_close(struct reftable_reader *r)
+int reftable_reader_init_log_iterator(struct reftable_reader *r,
+				      struct reftable_iterator *it)
 {
-	block_source_close(&r->source);
-	FREE_AND_NULL(r->name);
+	return reader_init_iter(r, it, BLOCK_TYPE_LOG);
 }
 
-int reftable_new_reader(struct reftable_reader **p,
-			struct reftable_block_source *src, char const *name)
+int reftable_reader_new(struct reftable_reader **out,
+			struct reftable_block_source *source, char const *name)
 {
-	struct reftable_reader *rd = reftable_calloc(1, sizeof(*rd));
-	int err = init_reader(rd, src, name);
-	if (err == 0) {
-		*p = rd;
-	} else {
-		block_source_close(src);
-		reftable_free(rd);
+	struct reftable_block footer = { 0 };
+	struct reftable_block header = { 0 };
+	struct reftable_reader *r;
+	uint64_t file_size = block_source_size(source);
+	uint32_t read_size;
+	int err;
+
+	REFTABLE_CALLOC_ARRAY(r, 1);
+	if (!r) {
+		err = REFTABLE_OUT_OF_MEMORY_ERROR;
+		goto done;
+	}
+
+	/*
+	 * We need one extra byte to read the type of first block. We also
+	 * pretend to always be reading v2 of the format because it is larger.
+	 */
+	read_size = header_size(2) + 1;
+	if (read_size > file_size) {
+		err = REFTABLE_FORMAT_ERROR;
+		goto done;
+	}
+
+	err = block_source_read_block(source, &header, 0, read_size);
+	if (err != read_size) {
+		err = REFTABLE_IO_ERROR;
+		goto done;
+	}
+
+	if (memcmp(header.data, "REFT", 4)) {
+		err = REFTABLE_FORMAT_ERROR;
+		goto done;
+	}
+	r->version = header.data[4];
+	if (r->version != 1 && r->version != 2) {
+		err = REFTABLE_FORMAT_ERROR;
+		goto done;
+	}
+
+	r->size = file_size - footer_size(r->version);
+	r->source = *source;
+	r->name = reftable_strdup(name);
+	if (!r->name) {
+		err = REFTABLE_OUT_OF_MEMORY_ERROR;
+		goto done;
+	}
+	r->hash_id = 0;
+	r->refcount = 1;
+
+	err = block_source_read_block(source, &footer, r->size,
+				      footer_size(r->version));
+	if (err != footer_size(r->version)) {
+		err = REFTABLE_IO_ERROR;
+		goto done;
+	}
+
+	err = parse_footer(r, footer.data, header.data);
+	if (err)
+		goto done;
+
+	*out = r;
+
+done:
+	reftable_block_done(&footer);
+	reftable_block_done(&header);
+	if (err) {
+		reftable_free(r);
+		block_source_close(source);
 	}
 	return err;
 }
 
-void reftable_reader_free(struct reftable_reader *r)
+void reftable_reader_incref(struct reftable_reader *r)
+{
+	if (!r->refcount)
+		BUG("cannot increment ref counter of dead reader");
+	r->refcount++;
+}
+
+void reftable_reader_decref(struct reftable_reader *r)
 {
 	if (!r)
 		return;
-	reader_close(r);
+	if (!r->refcount)
+		BUG("cannot decrement ref counter of dead reader");
+	if (--r->refcount)
+		return;
+	block_source_close(&r->source);
+	REFTABLE_FREE_AND_NULL(r->name);
 	reftable_free(r);
 }
 
@@ -681,7 +708,10 @@ static int reftable_reader_refs_for_indexed(struct reftable_reader *r,
 	struct indexed_table_ref_iter *itr = NULL;
 
 	/* Look through the reverse index. */
-	reader_init_iter(r, &oit, BLOCK_TYPE_OBJ);
+	err = reader_init_iter(r, &oit, BLOCK_TYPE_OBJ);
+	if (err < 0)
+		goto done;
+
 	err = iterator_seek(&oit, &want);
 	if (err != 0)
 		goto done;
@@ -699,7 +729,7 @@ static int reftable_reader_refs_for_indexed(struct reftable_reader *r,
 		goto done;
 	}
 
-	err = new_indexed_table_ref_iter(&itr, r, oid, hash_size(r->hash_id),
+	err = indexed_table_ref_iter_new(&itr, r, oid, hash_size(r->hash_id),
 					 got.u.obj.offsets,
 					 got.u.obj.offset_len);
 	if (err < 0)
@@ -724,23 +754,40 @@ static int reftable_reader_refs_for_unindexed(struct reftable_reader *r,
 	int err;
 
 	REFTABLE_ALLOC_ARRAY(ti, 1);
+	if (!ti) {
+		err = REFTABLE_OUT_OF_MEMORY_ERROR;
+		goto out;
+	}
+
 	table_iter_init(ti, r);
 	err = table_iter_seek_start(ti, BLOCK_TYPE_REF, 0);
-	if (err < 0) {
-		reftable_free(ti);
-		return err;
-	}
+	if (err < 0)
+		goto out;
 
-	filter = reftable_malloc(sizeof(struct filtering_ref_iterator));
+	filter = reftable_malloc(sizeof(*filter));
+	if (!filter) {
+		err = REFTABLE_OUT_OF_MEMORY_ERROR;
+		goto out;
+	}
 	*filter = empty;
 
-	strbuf_add(&filter->oid, oid, oid_len);
-	reftable_table_from_reader(&filter->tab, r);
-	filter->double_check = 0;
+	err = reftable_buf_add(&filter->oid, oid, oid_len);
+	if (err < 0)
+		goto out;
+
 	iterator_from_table_iter(&filter->it, ti);
 
 	iterator_from_filtering_ref_iterator(it, filter);
-	return 0;
+
+	err = 0;
+
+out:
+	if (err < 0) {
+		if (ti)
+			table_iter_close(ti);
+		reftable_free(ti);
+	}
+	return err;
 }
 
 int reftable_reader_refs_for(struct reftable_reader *r,
@@ -761,66 +808,6 @@ uint64_t reftable_reader_min_update_index(struct reftable_reader *r)
 	return r->min_update_index;
 }
 
-/* generic table interface. */
-
-static void reftable_reader_init_iter_void(void *tab,
-					   struct reftable_iterator *it,
-					   uint8_t typ)
-{
-	reader_init_iter(tab, it, typ);
-}
-
-static uint32_t reftable_reader_hash_id_void(void *tab)
-{
-	return reftable_reader_hash_id(tab);
-}
-
-static uint64_t reftable_reader_min_update_index_void(void *tab)
-{
-	return reftable_reader_min_update_index(tab);
-}
-
-static uint64_t reftable_reader_max_update_index_void(void *tab)
-{
-	return reftable_reader_max_update_index(tab);
-}
-
-static struct reftable_table_vtable reader_vtable = {
-	.init_iter = reftable_reader_init_iter_void,
-	.hash_id = reftable_reader_hash_id_void,
-	.min_update_index = reftable_reader_min_update_index_void,
-	.max_update_index = reftable_reader_max_update_index_void,
-};
-
-void reftable_table_from_reader(struct reftable_table *tab,
-				struct reftable_reader *reader)
-{
-	assert(!tab->ops);
-	tab->ops = &reader_vtable;
-	tab->table_arg = reader;
-}
-
-
-int reftable_reader_print_file(const char *tablename)
-{
-	struct reftable_block_source src = { NULL };
-	int err = reftable_block_source_from_file(&src, tablename);
-	struct reftable_reader *r = NULL;
-	struct reftable_table tab = { NULL };
-	if (err < 0)
-		goto done;
-
-	err = reftable_new_reader(&r, &src, tablename);
-	if (err < 0)
-		goto done;
-
-	reftable_table_from_reader(&tab, r);
-	err = reftable_table_print(&tab);
-done:
-	reftable_reader_free(r);
-	return err;
-}
-
 int reftable_reader_print_blocks(const char *tablename)
 {
 	struct {
@@ -850,7 +837,7 @@ int reftable_reader_print_blocks(const char *tablename)
 	if (err < 0)
 		goto done;
 
-	err = reftable_new_reader(&r, &src, tablename);
+	err = reftable_reader_new(&r, &src, tablename);
 	if (err < 0)
 		goto done;
 
@@ -881,7 +868,7 @@ int reftable_reader_print_blocks(const char *tablename)
 	}
 
 done:
-	reftable_reader_free(r);
+	reftable_reader_decref(r);
 	table_iter_close(&ti);
 	return err;
 }