Initial import.
diff --git a/src/core/channel/http_client_filter.c b/src/core/channel/http_client_filter.c
new file mode 100644
index 0000000..b82c735
--- /dev/null
+++ b/src/core/channel/http_client_filter.c
@@ -0,0 +1,143 @@
+/*
+ *
+ * Copyright 2014, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ * * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#include "src/core/channel/http_client_filter.h"
+#include <grpc/support/log.h>
+
+typedef struct call_data {
+ int unused; /* C89 requires at least one struct element */
+} call_data;
+
+typedef struct channel_data { grpc_mdelem *te_trailers; } channel_data;
+
+/* used to silence 'variable not used' warnings */
+static void ignore_unused(void *ignored) {}
+
+/* Called either:
+ - in response to an API call (or similar) from above, to send something
+ - a network event (or similar) from below, to receive something
+ op contains type and call direction information, in addition to the data
+ that is being sent or received. */
+static void call_op(grpc_call_element *elem, grpc_call_op *op) {
+ /* grab pointers to our data from the call element */
+ call_data *calld = elem->call_data;
+ channel_data *channeld = elem->channel_data;
+ GRPC_CALL_LOG_OP(GPR_INFO, elem, op);
+
+ ignore_unused(calld);
+
+ switch (op->type) {
+ case GRPC_SEND_START:
+ /* just prior to starting, add a te: trailers header */
+ grpc_call_element_send_metadata(elem, channeld->te_trailers);
+ grpc_call_next_op(elem, op);
+ break;
+ default:
+ /* pass control up or down the stack depending on op->dir */
+ grpc_call_next_op(elem, op);
+ break;
+ }
+}
+
+/* Called on special channel events, such as disconnection or new incoming
+ calls on the server */
+static void channel_op(grpc_channel_element *elem, grpc_channel_op *op) {
+ /* grab pointers to our data from the channel element */
+ channel_data *channeld = elem->channel_data;
+
+ ignore_unused(channeld);
+
+ switch (op->type) {
+ default:
+ /* pass control up or down the stack depending on op->dir */
+ grpc_channel_next_op(elem, op);
+ break;
+ }
+}
+
+/* Constructor for call_data */
+static void init_call_elem(grpc_call_element *elem,
+ const void *server_transport_data) {
+ /* grab pointers to our data from the call element */
+ call_data *calld = elem->call_data;
+ channel_data *channeld = elem->channel_data;
+
+ ignore_unused(channeld);
+
+ /* initialize members */
+ calld->unused = 0;
+}
+
+/* Destructor for call_data */
+static void destroy_call_elem(grpc_call_element *elem) {
+ /* grab pointers to our data from the call element */
+ call_data *calld = elem->call_data;
+ channel_data *channeld = elem->channel_data;
+
+ ignore_unused(calld);
+ ignore_unused(channeld);
+}
+
+/* Constructor for channel_data */
+static void init_channel_elem(grpc_channel_element *elem,
+ const grpc_channel_args *args, grpc_mdctx *mdctx,
+ int is_first, int is_last) {
+ /* grab pointers to our data from the channel element */
+ channel_data *channeld = elem->channel_data;
+
+ /* The first and the last filters tend to be implemented differently to
+ handle the case that there's no 'next' filter to call on the up or down
+ path */
+ GPR_ASSERT(!is_first);
+ GPR_ASSERT(!is_last);
+
+ /* initialize members */
+ channeld->te_trailers = grpc_mdelem_from_strings(mdctx, "te", "trailers");
+}
+
+/* Destructor for channel data */
+static void destroy_channel_elem(grpc_channel_element *elem) {
+ /* grab pointers to our data from the channel element */
+ channel_data *channeld = elem->channel_data;
+
+ grpc_mdelem_unref(channeld->te_trailers);
+}
+
+const grpc_channel_filter grpc_http_client_filter = {
+ call_op, channel_op,
+
+ sizeof(call_data), init_call_elem, destroy_call_elem,
+
+ sizeof(channel_data), init_channel_elem, destroy_channel_elem,
+
+ "http-client"};