Add a new method ReadUntilComplete to FileStream which ensures that all requested bytes are read from the file in one call, assuming no errors occurr or EOF is reached.

Review URL: http://codereview.chromium.org/21363

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@9803 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 21 insertions, 0 deletions

diff --git a/net/base/file_stream_posix.cc b/net/base/file_stream_posix.cc
index 7b248a4..151cf5d 100644
--- a/net/base/file_stream_posix.cc
+++ b/net/base/file_stream_posix.cc
@@ -154,6 +154,27 @@ int FileStream::Read(
   }
 }
 
+int FileStream::ReadUntilComplete(char *buf, int buf_len) {
+  int to_read = buf_len;
+  int bytes_total = 0;
+
+  do {
+    int bytes_read = Read(buf, to_read, NULL);
+    if (bytes_read <= 0) {
+      if (bytes_total == 0)
+        return bytes_read;
+
+      return bytes_total;
+    }
+
+    bytes_total += bytes_read;
+    buf += bytes_read;
+    to_read -= bytes_read;
+  } while (bytes_total < buf_len);
+
+  return bytes_total;
+}
+
 // TODO(deanm): async.
 int FileStream::Write(
     const char* buf, int buf_len, CompletionCallback* callback) {