Convert history file from readline format to replxx format

replxx requires each history line to prepended with time line:

    ### YYYY-MM-DD HH:MM:SS.SSS
    select 1

And w/o those service lines it will load all lines from history file as
one history line for suggestion. And if there are lots of lines in file it
will take lots of time (getline() + tons of reallocations).

base/common/ReplxxLineReader.cpp

@@ -1,8 +1,9 @@
 #include <common/ReplxxLineReader.h>
 #include <common/errnoToString.h>
 
-#include <errno.h>
+#include <chrono>
-#include <string.h>
+#include <cerrno>
+#include <cstring>
 #include <unistd.h>
 #include <functional>
 #include <sys/file.h>
@@ -24,6 +25,91 @@ void trim(String & s)
     s.erase(std::find_if(s.rbegin(), s.rend(), [](int ch) { return !std::isspace(ch); }).base(), s.end());
 }
 
+/// Copied from replxx::src/util.cxx::now_ms_str()
+std::string replxx_now_ms_str()
+{
+    std::chrono::milliseconds ms(std::chrono::duration_cast<std::chrono::milliseconds>(std::chrono::system_clock::now().time_since_epoch()));
+    time_t t = ms.count() / 1000;
+    tm broken;
+    if (!localtime_r(&t, &broken))
+    {
+        return std::string();
+    }
+
+    static int const BUFF_SIZE(32);
+    char str[BUFF_SIZE];
+    strftime(str, BUFF_SIZE, "%Y-%m-%d %H:%M:%S.", &broken);
+    snprintf(str + sizeof("YYYY-mm-dd HH:MM:SS"), 5, "%03d", static_cast<int>(ms.count() % 1000));
+    return str;
+}
+
+/// Convert from readline to replxx format.
+///
+/// replxx requires each history line to prepended with time line:
+///
+///     ### YYYY-MM-DD HH:MM:SS.SSS
+///     select 1
+///
+/// And w/o those service lines it will load all lines from history file as
+/// one history line for suggestion. And if there are lots of lines in file it
+/// will take lots of time (getline() + tons of reallocations).
+///
+/// NOTE: this code uses std::ifstream/std::ofstream like original replxx code.
+void convertHistoryFile(const std::string & path, replxx::Replxx & rx)
+{
+    std::ifstream in(path);
+    if (!in)
+    {
+        rx.print("Cannot open %s reading (for conversion): %s\n",
+            path.c_str(), errnoToString(errno).c_str());
+        return;
+    }
+
+    std::string line;
+    if (!getline(in, line).good())
+    {
+        rx.print("Cannot read from %s (for conversion): %s\n",
+            path.c_str(), errnoToString(errno).c_str());
+        return;
+    }
+
+    /// This is the marker of the date, no need to convert.
+    static char const REPLXX_TIMESTAMP_PATTERN[] = "### dddd-dd-dd dd:dd:dd.ddd";
+    if (line.starts_with("### ") && line.size() == strlen(REPLXX_TIMESTAMP_PATTERN))
+    {
+        return;
+    }
+
+    std::vector<std::string> lines;
+    in.seekg(0);
+    while (getline(in, line).good())
+    {
+        lines.push_back(line);
+    }
+    in.close();
+
+    size_t lines_size = lines.size();
+    std::sort(lines.begin(), lines.end());
+    lines.erase(std::unique(lines.begin(), lines.end()), lines.end());
+    rx.print("The history file (%s) is in old format. %zu lines, %zu unique lines.\n",
+        path.c_str(), lines_size, lines.size());
+
+    std::ofstream out(path);
+    if (!out)
+    {
+        rx.print("Cannot open %s for writing (for conversion): %s\n",
+            path.c_str(), errnoToString(errno).c_str());
+        return;
+    }
+
+    const std::string & timestamp = replxx_now_ms_str();
+    for (const auto & out_line : lines)
+    {
+        out << "### " << timestamp << "\n" << out_line << std::endl;
+    }
+    out.close();
+}
+
 }
 
 ReplxxLineReader::ReplxxLineReader(
@@ -47,6 +133,8 @@ ReplxxLineReader::ReplxxLineReader(
         }
         else
         {
+            convertHistoryFile(history_file_path, rx);
+
             if (flock(history_file_fd, LOCK_SH))
             {
                 rx.print("Shared lock of history file failed: %s\n", errnoToString(errno).c_str());

tests/queries/0_stateless/01933_client_replxx_convert_history.expect

@@ -0,0 +1,33 @@
+#!/usr/bin/expect -f
+
+log_user 0
+set timeout 60
+match_max 100000
+# A default timeout action is to do nothing, change it to fail
+expect_after {
+    timeout {
+        exit 1
+    }
+}
+set basedir [file dirname $argv0]
+
+exec bash -c "echo select 1 > $argv0.txt"
+exec bash -c "echo select 1 >> $argv0.txt"
+exec bash -c "echo select 1 >> $argv0.txt"
+
+spawn bash -c "source $basedir/../shell_config.sh ; \$CLICKHOUSE_CLIENT_BINARY \$CLICKHOUSE_CLIENT_OPT --history_file=$argv0.txt"
+expect "The history file ($argv0.txt) is in old format. 3 lines, 1 unique lines."
+expect ":) "
+send -- "\4"
+expect eof
+
+spawn bash -c "wc -l $argv0.txt"
+# The following lines are expected:
+#
+#     ### YYYY-MM-DD HH:MM:SS.SSS
+#     select 1
+#
+expect "2"
+expect eof
+
+exec bash -c "rm $argv0.txt"

tests/queries/skip_list.json

@@ -851,6 +851,7 @@
         "01913_replace_dictionary",
         "01914_exchange_dictionaries",
         "01915_create_or_replace_dictionary",
-        "01925_test_storage_merge_aliases"
+        "01925_test_storage_merge_aliases",
+        "01933_client_replxx_convert_history" /// Uses non unique history file
     ]
 }