[DO NOT MERGE] btif: Lighter weight file existence check

We switch from the heavier weight fopen() to using access() to
check for file existence and readability.  This avoids some of
the file opening overhead we don't need here.

Bug: b/117993149
Test: TreeHugger
Change-Id: Ib47b24e9d96803b7822535f9f566aa7818b38953
Merged-In: Ib47b24e9d96803b7822535f9f566aa7818b38953

diff --git a/btif/src/btif_config.cc b/btif/src/btif_config.cc
index bc11ca0..2eaf294 100644 (file)
--- a/btif/src/btif_config.cc
+++ b/btif/src/btif_config.cc
@@ -604,11 +604,8 @@ static std::string hash_file(const char* filename) {
 
 static std::string read_checksum_file(const char* checksum_filename) {
   // Ensure file exists
-  FILE* fp = fopen(checksum_filename, "rb");
-  if (!fp) {
+  if (access(checksum_filename, R_OK) != 0) {
     return "";
-  } else {
-    fclose(fp);
   }
   std::string output = btifKeystore.Decrypt(checksum_filename);
   return output;