From 4f31000cf40b5ff512e3bf7f3c0504054410b37e Mon Sep 17 00:00:00 2001
From: Tao He <linzhu.ht@alibaba-inc.com>
Date: Fri, 12 Feb 2021 15:56:09 +0800
Subject: [PATCH] Set a proper upper bound for `ls` request, and remove the
 default sort options. (#46)

Signed-off-by: Tao He <linzhu.ht@alibaba-inc.com>
---
 src/v3/AsyncGetAction.cpp | 37 +++++++++++++++++++++++++++++--------
 1 file changed, 29 insertions(+), 8 deletions(-)

diff --git a/src/v3/AsyncGetAction.cpp b/src/v3/AsyncGetAction.cpp
index c89c812..957d863 100644
--- a/src/v3/AsyncGetAction.cpp
+++ b/src/v3/AsyncGetAction.cpp
@@ -1,23 +1,44 @@
 #include "etcd/v3/AsyncGetAction.hpp"
+
+#include <cstdlib>
+
 #include "etcd/v3/action_constants.hpp"
 
 using etcdserverpb::RangeRequest;
 
+static std::string string_plus_one(std::string const &value) {
+  char *s = static_cast<char *>(calloc(value.size() + 1, sizeof(char)));
+  std::memcpy(s, value.c_str(), value.size());
+  for (int i = value.size() - 1; i >= 0; --i) {
+    if (static_cast<unsigned char>(s[i]) < 0xff) {
+      s[i] = s[i] + 1;
+      std::string ret = std::string(s, i + 1);
+      free(s);
+      return ret;
+    }
+  }
+  // see: noPrefixEnd in etcd
+  return {"\0"};
+}
+
 etcdv3::AsyncGetAction::AsyncGetAction(etcdv3::ActionParameters param)
   : etcdv3::Action(param)
 {
   RangeRequest get_request;
-  get_request.set_key(parameters.key);
+  if (parameters.key.empty()) {
+    get_request.set_key("\0");
+  } else {
+    get_request.set_key(parameters.key);
+  }
   get_request.set_limit(param.limit);
   if(parameters.withPrefix)
   {
-    std::string range_end(parameters.key); 
-    int ascii = (int)range_end[range_end.length()-1];
-    range_end.back() = ascii+1;
-
-    get_request.set_range_end(range_end);
-    get_request.set_sort_target(RangeRequest::SortTarget::RangeRequest_SortTarget_KEY);
-    get_request.set_sort_order(RangeRequest::SortOrder::RangeRequest_SortOrder_ASCEND);
+    if (parameters.key.empty()) {
+      get_request.set_range_end(string_plus_one("\0"));
+    } else {
+      get_request.set_range_end(string_plus_one(parameters.key));
+    }
+    get_request.set_sort_order(RangeRequest::SortOrder::RangeRequest_SortOrder_NONE);
   }   
   response_reader = parameters.kv_stub->AsyncRange(&context,get_request,&cq_);
   response_reader->Finish(&reply, &status, (void*)this);