Merge pull request #1076 from pagespeed/morlovich-h2-bit

Store whether h2 is in use in RequestContext.

src/ngx_pagespeed.cc

@@ -1086,6 +1086,17 @@ char* ps_merge_srv_conf(ngx_conf_t* cf, void* parent, void* child) {
   cfg_m->driver_factory->set_main_conf(parent_cfg_s->options);
   cfg_s->server_context = cfg_m->driver_factory->MakeNgxServerContext(
       "dummy_hostname", dummy_port);
+
+#if (NGX_HTTP_V2)
+  // Save the variable index of the "http2" variable, so we can use it
+  // at request time to lookup whether that's on. We do this conditionally
+  // since NGINX will complain to the user (at [emerg] level!) if it doesn't
+  // know about it.
+  ngx_str_t name = ngx_string("http2");
+  cfg_s->server_context->set_ngx_http2_variable_index(
+      ngx_http_get_variable_index(cf, &name));
+#endif
+
   // The server context sets some options when we call global_options(). So
   // let it do that, then merge in options we got from the config file.
   // Once we do that we're done with cfg_s->options.

src/ngx_server_context.cc

@@ -35,7 +35,8 @@ namespace net_instaweb {
 
 NgxServerContext::NgxServerContext(
     NgxRewriteDriverFactory* factory, StringPiece hostname, int port)
-    : SystemServerContext(factory, hostname, port) {
+    : SystemServerContext(factory, hostname, port),
+      ngx_http2_variable_index_(NGX_ERROR) {
 }
 
 NgxServerContext::~NgxServerContext() { }
@@ -70,11 +71,23 @@ SystemRequestContext* NgxServerContext::NewRequestContext(
     local_ip.len = 0;
   }
 
-  return new SystemRequestContext(thread_system()->NewMutex(),
-                                  timer(),
-                                  ps_determine_host(r),
-                                  local_port,
-                                  str_to_string_piece(local_ip));
+  SystemRequestContext* ctx = new SystemRequestContext(
+      thread_system()->NewMutex(), timer(),
+      ps_determine_host(r), local_port, str_to_string_piece(local_ip));
+
+  // See if http2 is in use.
+  if (ngx_http2_variable_index_ >= 0) {
+    ngx_http_variable_value_t* val =
+        ngx_http_get_indexed_variable(r, ngx_http2_variable_index_);
+    if (val != NULL && val->valid) {
+      StringPiece str_val(reinterpret_cast<char*>(val->data), val->len);
+      if (str_val == "h2" || str_val == "h2c") {
+        ctx->set_using_http2(true);
+      }
+    }
+  }
+
+  return ctx;
 }
 
 GoogleString NgxServerContext::FormatOption(StringPiece option_name,

src/ngx_server_context.h

@@ -58,8 +58,18 @@ class NgxServerContext : public SystemServerContext {
 
   virtual GoogleString FormatOption(StringPiece option_name, StringPiece args);
 
+  void set_ngx_http2_variable_index(ngx_int_t idx) {
+    ngx_http2_variable_index_ = idx;
+  }
+
+  ngx_int_t ngx_http2_variable_index() const {
+    return ngx_http2_variable_index_;
+  }
+
  private:
   NgxRewriteDriverFactory* ngx_factory_;
+  // what index the "http2" var is, or NGX_ERROR.
+  ngx_int_t ngx_http2_variable_index_;
 
   DISALLOW_COPY_AND_ASSIGN(NgxServerContext);
 };