3 files changed, 19 insertions, 11 deletions

diff --git a/src/core/lib/http/httpcli.c b/src/core/lib/http/httpcli.c
index 18135bcb58..7f3c2d120d 100644
--- a/src/core/lib/http/httpcli.c
+++ b/src/core/lib/http/httpcli.c
@@ -146,7 +146,7 @@ static void on_read(grpc_exec_ctx *exec_ctx, void *user_data,
     if (GPR_SLICE_LENGTH(req->incoming.slices[i])) {
       req->have_read_byte = 1;
       grpc_error *err =
-          grpc_http_parser_parse(&req->parser, req->incoming.slices[i]);
+          grpc_http_parser_parse(&req->parser, req->incoming.slices[i], NULL);
       if (err != GRPC_ERROR_NONE) {
         finish(exec_ctx, req, err);
         return;
diff --git a/src/core/lib/http/parser.c b/src/core/lib/http/parser.c
index d3bac5b876..cbf26811f7 100644
--- a/src/core/lib/http/parser.c
+++ b/src/core/lib/http/parser.c
@@ -33,6 +33,7 @@
 
 #include "src/core/lib/http/parser.h"
 
+#include <stdbool.h>
 #include <string.h>
 
 #include <grpc/support/alloc.h>
@@ -200,7 +201,8 @@ done:
   return error;
 }
 
-static grpc_error *finish_line(grpc_http_parser *parser) {
+static grpc_error *finish_line(grpc_http_parser *parser,
+                               bool *found_body_start) {
   grpc_error *err;
   switch (parser->state) {
     case GRPC_HTTP_FIRST_LINE:
@@ -211,6 +213,7 @@ static grpc_error *finish_line(grpc_http_parser *parser) {
     case GRPC_HTTP_HEADERS:
       if (parser->cur_line_length == parser->cur_line_end_length) {
         parser->state = GRPC_HTTP_BODY;
+        *found_body_start = true;
         break;
       }
       err = add_header(parser);
@@ -274,7 +277,8 @@ static bool check_line(grpc_http_parser *parser) {
   return false;
 }
 
-static grpc_error *addbyte(grpc_http_parser *parser, uint8_t byte) {
+static grpc_error *addbyte(grpc_http_parser *parser, uint8_t byte,
+                           bool *found_body_start) {
   switch (parser->state) {
     case GRPC_HTTP_FIRST_LINE:
     case GRPC_HTTP_HEADERS:
@@ -287,7 +291,7 @@ static grpc_error *addbyte(grpc_http_parser *parser, uint8_t byte) {
       parser->cur_line[parser->cur_line_length] = byte;
       parser->cur_line_length++;
       if (check_line(parser)) {
-        return finish_line(parser);
+        return finish_line(parser, found_body_start);
       }
       return GRPC_ERROR_NONE;
     case GRPC_HTTP_BODY:
@@ -329,14 +333,16 @@ void grpc_http_response_destroy(grpc_http_response *response) {
   gpr_free(response->hdrs);
 }
 
-grpc_error *grpc_http_parser_parse(grpc_http_parser *parser, gpr_slice slice) {
-  size_t i;
-
-  for (i = 0; i < GPR_SLICE_LENGTH(slice); i++) {
-    grpc_error *err = addbyte(parser, GPR_SLICE_START_PTR(slice)[i]);
+grpc_error *grpc_http_parser_parse(grpc_http_parser *parser, gpr_slice slice,
+                                   size_t *start_of_body) {
+  for (size_t i = 0; i < GPR_SLICE_LENGTH(slice); i++) {
+    bool found_body_start = false;
+    grpc_error *err = addbyte(parser, GPR_SLICE_START_PTR(slice)[i],
+                              &found_body_start);
     if (err != GRPC_ERROR_NONE) return err;
+    if (found_body_start && start_of_body != NULL)
+      *start_of_body = i + 1;
   }
-
   return GRPC_ERROR_NONE;
 }
 
diff --git a/src/core/lib/http/parser.h b/src/core/lib/http/parser.h
index 6df3cc8b13..fab42979cd 100644
--- a/src/core/lib/http/parser.h
+++ b/src/core/lib/http/parser.h
@@ -113,7 +113,9 @@ void grpc_http_parser_init(grpc_http_parser *parser, grpc_http_type type,
                            void *request_or_response);
 void grpc_http_parser_destroy(grpc_http_parser *parser);
 
-grpc_error *grpc_http_parser_parse(grpc_http_parser *parser, gpr_slice slice);
+/* Sets \a start_of_body to the offset in \a slice of the start of the body. */
+grpc_error *grpc_http_parser_parse(grpc_http_parser *parser, gpr_slice slice,
+                                   size_t *start_of_body);
 grpc_error *grpc_http_parser_eof(grpc_http_parser *parser);
 
 void grpc_http_request_destroy(grpc_http_request *request);