From 40dcb60bd748459082a0117bb5deb5aba1169a45 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?S=C3=A9bastien=20Noel?= <sebastien@twolife.be>
Date: Mon, 7 Oct 2024 13:08:36 +0200
Subject: [PATCH] honor the $XDG_CACHE_HOME env variable

---
 Descent3/init.cpp |  8 +-------
 ddio/ddio.h       |  6 ++++++
 ddio/file.cpp     | 27 +++++++++++++++++++++++++++
 3 files changed, 34 insertions(+), 7 deletions(-)

diff --git a/Descent3/init.cpp b/Descent3/init.cpp
index fcec5fce7..05810858f 100644
--- a/Descent3/init.cpp
+++ b/Descent3/init.cpp
@@ -1957,13 +1957,7 @@ void SetupTempDirectory(void) {
   if (t_arg) {
     Descent3_temp_directory = GameArgs[t_arg + 1];
   } else {
-    std::error_code ec;
-    std::filesystem::path tempPath = std::filesystem::temp_directory_path(ec);
-    if (ec) {
-      Error("Could not find temporary directory: \"%s\"", ec.message().c_str() );
-      exit(1);
-    }
-    Descent3_temp_directory = tempPath / "Descent3" / "cache";
+    Descent3_temp_directory = ddio_GetTempPath();
   }
 
   std::error_code ec;
diff --git a/ddio/ddio.h b/ddio/ddio.h
index d747f81b7..78a827be6 100644
--- a/ddio/ddio.h
+++ b/ddio/ddio.h
@@ -412,4 +412,10 @@ bool ddio_CreateLockFile(const std::filesystem::path &dir);
  */
 bool ddio_DeleteLockFile(const std::filesystem::path &dir);
 
+/**
+ * Gets path where to write temporary/cache files.
+ * @return path where user can write cache files.
+ */
+std::filesystem::path ddio_GetTempPath();
+
 #endif
diff --git a/ddio/file.cpp b/ddio/file.cpp
index 367736883..53641bebf 100644
--- a/ddio/file.cpp
+++ b/ddio/file.cpp
@@ -192,3 +192,30 @@ std::filesystem::path ddio_GetTmpFileName(const std::filesystem::path &basedir,
   mem_free(random_name);
   return result;
 }
+
+std::filesystem::path ddio_GetTempPath() {
+  std::filesystem::path result;
+
+#if defined(POSIX)
+  char *envr = SDL_getenv("XDG_CACHE_HOME");
+  if (envr) {
+    result = std::filesystem::path(envr) / "Descent3";
+  } else {
+    envr = SDL_getenv("HOME");
+    if (envr) {
+      result = std::filesystem::path(envr) / ".cache" / "Descent3";
+    } else {
+#endif
+      std::error_code ec;
+      std::filesystem::path tempPath = std::filesystem::temp_directory_path(ec);
+      if (ec) {
+        Error("Could not find temporary directory: \"%s\"", ec.message().c_str() );
+        exit(1);
+      }
+      result = tempPath / "Descent3" / "cache";
+#if defined(POSIX)
+    }
+  }
+#endif
+  return result;
+}