3 files changed, 49 insertions, 0 deletions
diff --git a/net/base/file_stream.h b/net/base/file_stream.h
index 20466b4..eaf6a0d 100644
--- a/net/base/file_stream.h
+++ b/net/base/file_stream.h
@@ -81,6 +81,13 @@ class FileStream {
   // You can pass NULL as the callback for synchronous I/O.
   int Read(char* buf, int buf_len, CompletionCallback* callback);
 
+  // Performs the same as Read, but ensures that exactly buf_len bytes
+  // are copied into buf.  A partial read may occur, but only as a result of
+  // end-of-file or fatal error.  Returns the number of bytes copied into buf,
+  // 0 if at end-of-file and no bytes have been read into buf yet,
+  // or an error code if the operation could not be performed.
+  int ReadUntilComplete(char *buf, int buf_len);
+
   // Call this method to write data at the current stream position.  Up to
   // buf_len bytes will be written from buf. (In other words, partial writes are
   // allowed.)  Returns the number of bytes written, or an error code if the 
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) {
diff --git a/net/base/file_stream_win.cc b/net/base/file_stream_win.cc
index ca492a2..1ab71df 100644
--- a/net/base/file_stream_win.cc
+++ b/net/base/file_stream_win.cc
@@ -234,6 +234,27 @@ int FileStream::Read(
   return rv;
 }
 
+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;
+}
+
 int FileStream::Write(
     const char* buf, int buf_len, CompletionCallback* callback) {
   if (!IsOpen())