Merged (squash) pull request "Add XDG Support": NVIDIA#250

These changes move the user data folder on Linux from ${HOME}/.quake2rtx to ${XDG_DATA_HOME}/quake2rtx in order to conform to the XDG specification, see https://specifications.freedesktop.org/basedir-spec/basedir-spec-latest.html
Files previously created in the old location are moved to the new location by q2rtx.sh.

setup/find-retail-paks.sh

@@ -1,6 +1,10 @@
 #!/bin/bash
 
-DEST_DIR="${HOME}/.quake2rtx"
+if [[ -n "${XDG_DATA_HOME}" ]]; then
+	XDG_DATA_HOME = "${HOME}/.local/share"
+fi
+
+DEST_DIR="${XDG_DATA_HOME}/quake2rtx"
 
 # Check for zenity/yad
 ZEN=""

setup/q2rtx.sh

@@ -2,21 +2,28 @@
 
 BIN_PREFIX="."
 
+mkdir -p "${XDG_DATA_HOME:="${HOME}/.local/share"}"
+
 # If the game is installed via a package manager q2rtx won't be in the same
 # directory as q2rtx.sh
 if [[ -d "/usr/share/quake2rtx" ]]; then
 	BIN_PREFIX="/usr/share/quake2rtx/bin"
 fi
 
+if [[ -d "${HOME}/.quake2rtx"  && ! -d "${XDG_DATA_HOME}/quake2rtx" ]]; then
+        mv "${HOME}/.quake2rtx" "${XDG_DATA_HOME}/quake2rtx"
+fi
+
+
 # Generate the user's game dir if doesn't exist
-if [[ ! -d "${HOME}/.quake2rtx/baseq2" ]]; then
-	mkdir -p "${HOME}/.quake2rtx/baseq2"
+if [[ ! -d "${XDG_DATA_HOME}/quake2rtx/baseq2" ]]; then
+	mkdir -p "${XDG_DATA_HOME}/quake2rtx/baseq2"
 fi
 
 # Only run this script on first-launch
-if [[ ! -f "${HOME}/.quake2rtx/.retail_checked" ]]; then
+if [[ ! -f "${XDG_DATA_HOME}/quake2rtx/.retail_checked" ]]; then
 	${BIN_PREFIX}/find-retail-paks.sh
-	touch ${HOME}/.quake2rtx/.retail_checked
+	touch ${XDG_DATA_HOME}/quake2rtx/.retail_checked
 fi
 
 ${BIN_PREFIX}/q2rtx "$@"

src/unix/system.c

@@ -31,6 +31,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include <sys/stat.h>
 #include <sys/time.h>
 #include <sys/mman.h>
+#include <stdlib.h>
 #include <unistd.h>
 #include <fcntl.h>
 #include <signal.h>
@@ -307,7 +308,9 @@ Sys_Init
 void Sys_Init(void)
 {
     char    *homedir;
+    char    *xdg_data_home_dir;
     char     homegamedir[PATH_MAX];
+    int      check_snprintf;
     cvar_t  *sys_parachute;
     DIR     *dir_hnd;
 
@@ -328,7 +331,7 @@ void Sys_Init(void)
     }
 
     if (!baseDirectory[0]) {
-	    Sys_Error("Game basedir not found!\n");
+        Sys_Error("Game basedir not found!\n");
     }
     // basedir <path>
     // allows the game to run from outside the data tree
@@ -338,9 +341,35 @@ void Sys_Init(void)
     // specifies per-user writable directory for demos, screenshots, etc
     homedir = getenv("HOME");
     if (!homedir) {
-	    Sys_Error("Homedir not found!\n");
+        Sys_Error("Homedir not found!\n");
+    }
+    // Attempt to respect user's XDG_DATA_HOME environment variable
+    xdg_data_home_dir = getenv("XDG_DATA_HOME");
+    if (!xdg_data_home_dir) {
+        size_t xdg_unset_len = strlen(homedir) + strlen("/.local/share") + 1;
+
+        xdg_data_home_dir = malloc(xdg_unset_len);
+
+        if (xdg_data_home_dir == NULL) {
+            Sys_Error("%s:xdg_data_home_dir: malloc() failed.\n", __func__);
+        }
+        check_snprintf = snprintf(xdg_data_home_dir, xdg_unset_len,
+            "%s/%s", homedir, ".local/share");
+            if (check_snprintf < 0) {
+                Sys_Error("xdg_data_home_dir: XDG_DATA_HOME not set, and "
+                    "storing the default path (${HOME}/.local/share) "
+                    "failed.\n");
+        }
+    }
+    check_snprintf = snprintf(homegamedir, sizeof(homegamedir),
+            "%s/%s", xdg_data_home_dir, "quake2rtx");
+
+    free(xdg_data_home_dir);
+
+    if (check_snprintf < 0) {
+            Sys_Error("%s:homegamedir: snprintf() failed with return "
+                    "value %d.\n", __func__, check_snprintf);
     }
-    sprintf(homegamedir, "%s/%s", homedir, ".quake2rtx");
     sys_homedir = Cvar_Get("homedir", homegamedir, CVAR_NOSET);
     sys_libdir = Cvar_Get("libdir", baseDirectory, CVAR_NOSET);
     sys_forcegamelib = Cvar_Get("sys_forcegamelib", "", CVAR_NOSET);