bloblist: Add a new function to add or check size

A common check is to see if a blob is present, create it if not and make
sure that the size is large enough. Add a function to handle this.

Signed-off-by: Simon Glass <sjg@chromium.org>

common/bloblist.c

@@ -85,8 +85,10 @@ static int bloblist_ensurerec(uint tag, struct bloblist_rec **recp, int size)
 
 	rec = bloblist_findrec(tag);
 	if (rec) {
-		if (size && size != rec->size)
+		if (size && size != rec->size) {
+			*recp = rec;
 			return -ESPIPE;
+		}
 	} else {
 		int ret;
 
@@ -145,6 +147,21 @@ void *bloblist_ensure(uint tag, int size)
 	return (void *)rec + rec->hdr_size;
 }
 
+int bloblist_ensure_size_ret(uint tag, int *sizep, void **blobp)
+{
+	struct bloblist_rec *rec;
+	int ret;
+
+	ret = bloblist_ensurerec(tag, &rec, *sizep);
+	if (ret == -ESPIPE)
+		*sizep = rec->size;
+	else if (ret)
+		return ret;
+	*blobp = (void *)rec + rec->hdr_size;
+
+	return 0;
+}
+
 static u32 bloblist_calc_chksum(struct bloblist_hdr *hdr)
 {
 	struct bloblist_rec *rec;

include/bloblist.h

@@ -151,6 +151,19 @@ int bloblist_ensure_size(uint tag, int size, void **blobp);
  */
 void *bloblist_ensure(uint tag, int size);
 
+/**
+ * bloblist_ensure_size_ret() - Find or add a blob
+ *
+ * Find an existing blob, or add a new one if not found
+ *
+ * @tag:	Tag to add (enum bloblist_tag_t)
+ * @sizep:	Size of the blob to create; returns size of actual blob
+ * @blobp:	Returns a pointer to blob on success
+ * @return 0 if OK, -ENOSPC if it is missing and could not be added due to lack
+ *	of space
+ */
+int bloblist_ensure_size_ret(uint tag, int *sizep, void **blobp);
+
 /**
  * bloblist_new() - Create a new, empty bloblist of a given size
  *

test/bloblist.c

@@ -24,6 +24,7 @@ enum {
 
 	TEST_SIZE		= 10,
 	TEST_SIZE2		= 20,
+	TEST_SIZE_LARGE		= 0xe0,
 
 	TEST_ADDR		= CONFIG_BLOBLIST_ADDR,
 	TEST_BLOBLIST_SIZE	= 0x100,
@@ -97,6 +98,39 @@ static int bloblist_test_blob(struct unit_test_state *uts)
 }
 BLOBLIST_TEST(bloblist_test_blob, 0);
 
+/* Check bloblist_ensure_size_ret() */
+static int bloblist_test_blob_ensure(struct unit_test_state *uts)
+{
+	void *data, *data2;
+	int size;
+
+	/* At the start there should be no records */
+	clear_bloblist();
+	ut_assertok(bloblist_new(TEST_ADDR, TEST_BLOBLIST_SIZE, 0));
+
+	/* Test with an empty bloblist */
+	size = TEST_SIZE;
+	ut_assertok(bloblist_ensure_size_ret(TEST_TAG, &size, &data));
+	ut_asserteq(TEST_SIZE, size);
+
+	/* Check that we get the same thing again */
+	ut_assertok(bloblist_ensure_size_ret(TEST_TAG, &size, &data2));
+	ut_asserteq(TEST_SIZE, size);
+	ut_asserteq_ptr(data, data2);
+
+	/* Check that the size remains the same */
+	size = TEST_SIZE2;
+	ut_assertok(bloblist_ensure_size_ret(TEST_TAG, &size, &data));
+	ut_asserteq(TEST_SIZE, size);
+
+	/* Check running out of space */
+	size = TEST_SIZE_LARGE;
+	ut_asserteq(-ENOSPC, bloblist_ensure_size_ret(TEST_TAG2, &size, &data));
+
+	return 0;
+}
+BLOBLIST_TEST(bloblist_test_blob_ensure, 0);
+
 static int bloblist_test_bad_blob(struct unit_test_state *uts)
 {
 	struct bloblist_hdr *hdr;