net: don't preserve 1xx responses in parser buffer.

net/http/http_stream_parser.cc

Index: net/http/http_stream_parser.cc
diff --git a/net/http/http_stream_parser.cc b/net/http/http_stream_parser.cc
index e53aafdac1cfd4871dd41d3cd2989d1ed6e1de27..9067bff9af02b0173446be685a1089b20dd3ee88 100644
--- a/net/http/http_stream_parser.cc
+++ b/net/http/http_stream_parser.cc
@@ -304,8 +304,9 @@ int HttpStreamParser::ReadResponseHeaders(const CompletionCallback& callback) {
 
   if (read_buf_->offset() > 0) {
     // Simulate the state where the data was just read from the socket.
-    result = read_buf_->offset() - read_buf_unused_offset_;
-    read_buf_->set_offset(read_buf_unused_offset_);
+    DCHECK_EQ(0, read_buf_unused_offset_);

[SkyLined, 2013/09/30 18:27:47]

Should we move this DCHECK to the start of the function?

[agl, 2013/09/30 20:59:28]

Done.

+    result = read_buf_->offset();
+    read_buf_->set_offset(0);
   }
   if (result > 0)
     io_state_ = STATE_READ_HEADERS_COMPLETE;
@@ -580,7 +581,8 @@ int HttpStreamParser::DoReadHeadersComplete(int result) {
   if (end_of_header_offset == -1) {
     io_state_ = STATE_READ_HEADERS;
     // Prevent growing the headers buffer indefinitely.
-    if (read_buf_->offset() - read_buf_unused_offset_ >= kMaxHeaderBufSize) {
+    DCHECK_EQ(0, read_buf_unused_offset_);

[SkyLined, 2013/09/30 18:27:47]

Should we move this DCHECK to the start of the function?

[agl, 2013/09/30 20:59:28]

Done.

+    if (read_buf_->offset() >= kMaxHeaderBufSize) {
       io_state_ = STATE_DONE;
       return ERR_RESPONSE_HEADERS_TOO_BIG;
     }
@@ -588,32 +590,34 @@ int HttpStreamParser::DoReadHeadersComplete(int result) {
     // Note where the headers stop.
     read_buf_unused_offset_ = end_of_header_offset;

[SkyLined, 2013/09/30 18:27:47]

This is only needed if the response contains a body. Otherwise the value gets
set to 0. It should therefore probably be moved down to just above line 620,
before "io_state_ = STATE_BODY_PENDING;".

[agl, 2013/09/30 20:59:28]

Done.

 
-    if (response_->headers->response_code() / 100 == 1) {
-      // After processing a 1xx response, the caller will ask for the next
-      // header, so reset state to support that.  We don't just skip these
-      // completely because 1xx codes aren't acceptable when establishing a
-      // tunnel.
-      io_state_ = STATE_REQUEST_SENT;
-      response_header_start_offset_ = -1;
-    } else {
-      io_state_ = STATE_BODY_PENDING;
-      CalculateResponseBodySize();
-      // If the body is 0, the caller may not call ReadResponseBody, which
-      // is where any extra data is copied to read_buf_, so we move the
-      // data here and transition to DONE.
-      if (response_body_length_ == 0) {
+    CalculateResponseBodySize();
+    // If the body is 0, the caller may not call ReadResponseBody, which
+    // is where any extra data is copied to read_buf_, so we move the
+    // data here.
+    if (response_body_length_ == 0) {
+      int extra_bytes = read_buf_->offset() - read_buf_unused_offset_;
+      if (extra_bytes) {
+        CHECK_GT(extra_bytes, 0);
+        memmove(read_buf_->StartOfBuffer(),
+                read_buf_->StartOfBuffer() + read_buf_unused_offset_,
+                extra_bytes);
+      }
+      read_buf_->SetCapacity(extra_bytes);
+      read_buf_unused_offset_ = 0;
+      if (response_->headers->response_code() / 100 == 1) {
+        // After processing a 1xx response, the caller will ask for the next
+        // header, so reset state to support that.  We don't just skip these
+        // completely because 1xx codes aren't acceptable when establishing a
+        // tunnel.
+        response_header_start_offset_ = -1;
+        response_body_length_ = -1;
+        io_state_ = STATE_REQUEST_SENT;
+      } else {
         io_state_ = STATE_DONE;
-        int extra_bytes = read_buf_->offset() - read_buf_unused_offset_;
-        if (extra_bytes) {
-          CHECK_GT(extra_bytes, 0);
-          memmove(read_buf_->StartOfBuffer(),
-                  read_buf_->StartOfBuffer() + read_buf_unused_offset_,
-                  extra_bytes);
-        }
-        read_buf_->SetCapacity(extra_bytes);
-        read_buf_unused_offset_ = 0;
-        return OK;
       }
+      return OK;
+    } else {
+      io_state_ = STATE_BODY_PENDING;
     }
   }
   return result;
@@ -754,16 +758,16 @@ int HttpStreamParser::ParseResponseHeaders() {
 
   // Look for the start of the status line, if it hasn't been found yet.
   if (response_header_start_offset_ < 0) {
+    DCHECK_EQ(0, read_buf_unused_offset_);

[SkyLined, 2013/09/30 18:27:47]

Should we move this DCHECK to the start of the function?

[agl, 2013/09/30 20:59:28]

Done.

     response_header_start_offset_ = HttpUtil::LocateStartOfStatusLine(
-        read_buf_->StartOfBuffer() + read_buf_unused_offset_,
-        read_buf_->offset() - read_buf_unused_offset_);
+        read_buf_->StartOfBuffer(), read_buf_->offset());
   }
 
   if (response_header_start_offset_ >= 0) {
-    end_offset = HttpUtil::LocateEndOfHeaders(
-        read_buf_->StartOfBuffer() + read_buf_unused_offset_,
-        read_buf_->offset() - read_buf_unused_offset_,
-        response_header_start_offset_);
+    DCHECK_EQ(0, read_buf_unused_offset_);

[SkyLined, 2013/09/30 18:27:47]

Should we move this DCHECK to the start of the function?

[agl, 2013/09/30 20:59:28]

Done.

+    end_offset = HttpUtil::LocateEndOfHeaders(read_buf_->StartOfBuffer(),
+                                              read_buf_->offset(),
+                                              response_header_start_offset_);
   } else if (read_buf_->offset() - read_buf_unused_offset_ >= 8) {
     // Enough data to decide that this is an HTTP/0.9 response.
     // 8 bytes = (4 bytes of junk) + "http".length()
@@ -776,7 +780,8 @@ int HttpStreamParser::ParseResponseHeaders() {
   int rv = DoParseResponseHeaders(end_offset);
   if (rv < 0)
     return rv;
-  return end_offset + read_buf_unused_offset_;
+  DCHECK_EQ(0, read_buf_unused_offset_);

[SkyLined, 2013/09/30 18:27:47]

Should we move this DCHECK to the start of the function?

[agl, 2013/09/30 20:59:28]

Done.

+  return end_offset;
 }
 
 int HttpStreamParser::DoParseResponseHeaders(int end_offset) {
@@ -830,13 +835,16 @@ void HttpStreamParser::CalculateResponseBodySize() {
   // (informational), 204 (no content), and 304 (not modified) responses
   // MUST NOT include a message-body. All other responses do include a
   // message-body, although it MAY be of zero length.
-  switch (response_->headers->response_code()) {
-    // Note that 1xx was already handled earlier.
-    case 204:  // No Content
-    case 205:  // Reset Content
-    case 304:  // Not Modified
-      response_body_length_ = 0;
-      break;
+  if (response_->headers->response_code() / 100 == 1) {
+    response_body_length_ = 0;
+  } else {
+    switch (response_->headers->response_code()) {
+      case 204:  // No Content
+      case 205:  // Reset Content
+      case 304:  // Not Modified
+        response_body_length_ = 0;
+        break;
+    }
   }
   if (request_->method == "HEAD")
     response_body_length_ = 0;