From e5048b3a8084d4ec8e1db76cde03d108a316003b Mon Sep 17 00:00:00 2001
From: Robert Sesek <rsesek@chromium.org>
Date: Fri, 7 Nov 2014 12:08:14 -0500
Subject: [PATCH] In CompositeHTTPBodyStream, coalesce small GetBytesBuffer()s
 to better fill the buffer.

R=mark@chromium.org

Review URL: https://codereview.chromium.org/707223002
---
 util/net/http_body.cc      | 27 ++++++++++++++++-----------
 util/net/http_body_test.cc |  2 +-
 2 files changed, 17 insertions(+), 12 deletions(-)

diff --git a/util/net/http_body.cc b/util/net/http_body.cc
index cd31ab4f..0e5daa34 100644
--- a/util/net/http_body.cc
+++ b/util/net/http_body.cc
@@ -97,20 +97,25 @@ CompositeHTTPBodyStream::~CompositeHTTPBodyStream() {
 }
 
 ssize_t CompositeHTTPBodyStream::GetBytesBuffer(uint8_t* buffer,
-                                                size_t max_len) {
-  if (current_part_ == parts_.end())
-    return 0;
+                                                size_t buffer_len) {
+  ssize_t max_len = std::min(
+      buffer_len, implicit_cast<size_t>(std::numeric_limits<ssize_t>::max()));
+  ssize_t bytes_copied = 0;
+  while (bytes_copied < max_len && current_part_ != parts_.end()) {
+    ssize_t this_read = (*current_part_)->GetBytesBuffer(
+        buffer + bytes_copied, max_len - bytes_copied);
 
-  ssize_t rv = (*current_part_)->GetBytesBuffer(buffer, max_len);
-
-  if (rv == 0) {
-    // If the current part has returned 0 indicating EOF, advance the current
-    // part and call recursively to try again.
-    ++current_part_;
-    return GetBytesBuffer(buffer, max_len);
+    if (this_read == 0) {
+      // If the current part has returned 0 indicating EOF, advance the current
+      // part and try again.
+      ++current_part_;
+    } else if (this_read < 0) {
+      return this_read;
+    }
+    bytes_copied += this_read;
   }
 
-  return rv;
+  return bytes_copied;
 }
 
 }  // namespace crashpad
diff --git a/util/net/http_body_test.cc b/util/net/http_body_test.cc
index d6504978..c59b6d6b 100644
--- a/util/net/http_body_test.cc
+++ b/util/net/http_body_test.cc
@@ -214,7 +214,7 @@ TEST_P(CompositeHTTPBodyStreamBufferSize, StringsAndFile) {
 
 INSTANTIATE_TEST_CASE_P(VariableBufferSize,
                         CompositeHTTPBodyStreamBufferSize,
-                        testing::Values(1, 2, 9, 16, 31, 128));
+                        testing::Values(1, 2, 9, 16, 31, 128, 1024));
 
 }  // namespace
 }  // namespace test