improve cmd:match (multimatch); fix missing 'delete's

CMakeLists.txt

@@ -1,7 +1,7 @@
 cmake_minimum_required(VERSION 3.0)
 project(zstreedb2 CXX)
 set(INSTALL_BIN_DIR bin CACHE PATH "Installation directory for binaries")
-set(CMAKE_CXX_STANDARD 14)
+set(CMAKE_CXX_STANDARD 17)
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
 
 find_package(Threads REQUIRED)

main.cxx

@@ -4,8 +4,11 @@
  **/
 
 #include <stdio.h>
+#include <stdlib.h>
+#include <algorithm>
 #include <thread>
 #include <unordered_map>
+#include <utility>
 #include <rocksdb/db.h>
 
 #include "args.hpp"
@@ -20,6 +23,41 @@ static void cleanup() {
   delete db;
 }
 
+static void filter_match(vector<string> &selv, string &&key, const string &value) {
+  vector<rocksdb::Status> sts;
+  vector<string> values;
+
+  // 1. retrieve values
+  {
+    string sufx = "." + move(key);
+    vector<string> keys;
+    vector<rocksdb::Slice> key_slices;
+    keys.reserve(selv.size());
+    key_slices.reserve(selv.size());
+    for(const auto &i : selv)
+      key_slices.emplace_back(keys.emplace_back(i + sufx));
+    string().swap(sufx);
+    sts = db->MultiGet({}, key_slices, &values);
+  }
+
+  // 2. find matches
+  {
+    auto it_s = sts.begin();
+    auto it_v = values.begin();
+    auto it_sel = selv.begin();
+
+    while(it_sel != selv.end()) {
+      if(!it_s->ok() || *it_v != value) {
+        it_s = sts.erase(it_s);
+        it_v = values.erase(it_v);
+        it_sel = selv.erase(it_sel);
+        continue;
+      }
+      ++it_s; ++it_v; ++it_sel;
+    }
+  }
+}
+
 #define AC(C) case ztdb::args_t::C:
 
 int main(const int argc, char *argv[]) {
@@ -51,7 +89,7 @@ int main(const int argc, char *argv[]) {
     if(!st.ok())
       errmsg(2, "db open failed: " + st.ToString());
   }
-
+  atexit(cleanup);
 
   switch(args.cmd) {
     AC(GET)
@@ -160,16 +198,31 @@ int main(const int argc, char *argv[]) {
     AC(MATCH)
       {
         if(args.cmd_args.empty())
-          errmsg(1, "invalid invocation to 'zstreedb2 m KEY VALUE'");
+          errmsg(1, "invalid invocation to 'zstreedb2 m (KEY VALUE)+'");
+
+        vector<string> selv;
+
+        {
+          const string key = "." + args.sel_node;
+          const auto it = db->NewIterator({});
+          for(it->SeekToFirst(); it->Valid(); it->Next())
+            if(it->key().ends_with(key) && it->value() == args.cmd_args.front()) {
+              auto slc = it->key();
+              slc.remove_suffix(key.size());
+              selv.emplace_back(slc.data(), slc.size());
+            }
+          delete it;
+        }
 
-        const string key = "." + args.sel_node;
-        const auto it = db->NewIterator({});
-        for(it->SeekToFirst(); it->Valid(); it->Next())
-          if(it->key().ends_with(key) && it->value() == args.cmd_args.front()) {
-            auto slc = it->key();
-            slc.remove_suffix(key.size());
-            printf("%.*s\n", static_cast<int>(slc.size()), slc.data());
-          }
+        args.cmd_args.erase(args.cmd_args.begin());
+        auto it = args.cmd_args.begin();
+        while(it != args.cmd_args.end() && (it + 1) != args.cmd_args.end()) {
+          filter_match(selv, std::move(*it), *(it + 1));
+          it += 2;
+        }
+
+        for(const auto &i : selv)
+          printf("%.*s\n", static_cast<int>(i.size()), i.data());
       }
       break;