From 5bd8795e1fa9255836fbbeab0a22f5038d92d53c Mon Sep 17 00:00:00 2001
From: Eelco Dolstra <edolstra@gmail.com>
Date: Tue, 25 Apr 2017 18:56:29 +0200
Subject: [PATCH] nix repl: Use $XDG_DATA_HOME for the readline history

---
 src/libutil/util.cc | 12 ++++++++++++
 src/libutil/util.hh |  3 +++
 src/nix/repl.cc     |  7 ++++---
 3 files changed, 19 insertions(+), 3 deletions(-)

diff --git a/src/libutil/util.cc b/src/libutil/util.cc
index 88a2f752c..026e49351 100644
--- a/src/libutil/util.cc
+++ b/src/libutil/util.cc
@@ -441,6 +441,18 @@ Path getConfigDir()
 }
 
 
+Path getDataDir()
+{
+    Path dataDir = getEnv("XDG_DATA_HOME");
+    if (dataDir.empty()) {
+        Path homeDir = getEnv("HOME");
+        if (homeDir.empty()) throw Error("$XDG_DATA_HOME and $HOME are not set");
+        dataDir = homeDir + "/.local/share";
+    }
+    return dataDir;
+}
+
+
 Paths createDirs(const Path & path)
 {
     Paths created;
diff --git a/src/libutil/util.hh b/src/libutil/util.hh
index ae40dcd4c..a9950f830 100644
--- a/src/libutil/util.hh
+++ b/src/libutil/util.hh
@@ -116,6 +116,9 @@ Path getCacheDir();
 /* Return $XDG_CONFIG_HOME or $HOME/.config. */
 Path getConfigDir();
 
+/* Return $XDG_DATA_HOME or $HOME/.local/share. */
+Path getDataDir();
+
 /* Create a directory and all its parents, if necessary.  Returns the
    list of created directories, in order of creation. */
 Paths createDirs(const Path & path);
diff --git a/src/nix/repl.cc b/src/nix/repl.cc
index 54e48e405..78d973ba8 100644
--- a/src/nix/repl.cc
+++ b/src/nix/repl.cc
@@ -29,9 +29,6 @@ using namespace std;
 #define ESC_CYA "\033[36m"
 #define ESC_END "\033[0m"
 
-string programId = "nix-repl";
-const string historyFile = string(getenv("HOME")) + "/.nix-repl-history";
-
 struct NixRepl
 {
     string curDir;
@@ -45,6 +42,8 @@ struct NixRepl
     int displ;
     StringSet varNames;
 
+    const Path historyFile;
+
     StringSet completions;
     StringSet::iterator curCompletion;
 
@@ -115,6 +114,7 @@ string removeWhitespace(string s)
 NixRepl::NixRepl(const Strings & searchPath, nix::ref<Store> store)
     : state(searchPath, store)
     , staticEnv(false, &state.staticBaseEnv)
+    , historyFile(getDataDir() + "/nix/repl-history")
 {
     curDir = absPath(".");
 }
@@ -140,6 +140,7 @@ void NixRepl::mainLoop(const Strings & files)
     // Allow nix-repl specific settings in .inputrc
     rl_readline_name = "nix-repl";
     using_history();
+    createDirs(dirOf(historyFile));
     read_history(historyFile.c_str());
 
     string input;