1 files changed, 116 insertions, 0 deletions
diff --git a/src/xdg.cc b/src/xdg.cc
new file mode 100644
index 0000000..b61b4ba
--- /dev/null
+++ b/src/xdg.cc
@@ -0,0 +1,116 @@
+#include "common.hh"
+
+#include "xdg.hh"
+
+#include <filesystem>
+#include <pwd.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+namespace xdg {
+
+namespace {
+
+bool valid(char const* path) {
+  return path && path[0] == '/';
+}
+
+bool valid(std::string const& path, size_t pos, size_t len) {
+  return len > 0 && path[pos] == '/';
+}
+
+std::filesystem::path get_home() {
+  auto* env = getenv("HOME");
+  if (valid(env))
+    return env;
+  auto* pwd = getpwuid(getuid());
+  if (pwd && valid(pwd->pw_dir))
+    return pwd->pw_dir;
+  return "/";
+}
+
+void get_paths(Type type, std::string* dirs, std::filesystem::path* home) {
+  char const* env;
+  switch (type) {
+  case Type::CONFIG:
+    if (dirs) {
+      env = getenv("XDG_CONFIG_DIRS");
+      if (valid(env)) {
+        dirs->assign(env);
+      } else {
+        dirs->assign("/etc/xdg");
+      }
+    }
+    if (home) {
+      env = getenv("XDG_CONFIG_HOME");
+      if (valid(env)) {
+        *home = env;
+      } else {
+        *home = get_home() / ".config";
+      }
+    }
+    break;
+  case Type::DATA:
+    if (dirs) {
+      env = getenv("XDG_DATA_DIRS");
+      if (valid(env)) {
+        dirs->assign(env);
+      } else {
+        dirs->assign("usr/local/share/:/usr/share/");
+      }
+    }
+    if (home) {
+      env = getenv("XDG_DATA_HOME");
+      if (valid(env)) {
+        *home = env;
+      } else {
+        *home = get_home() / ".local/share";
+      }
+    }
+    break;
+  case Type::CACHE:
+    if (dirs)
+      dirs->clear();
+    if (home) {
+      env = getenv("XDG_CACHE_HOME");
+      if (valid(env)) {
+        *home = env;
+      } else {
+        *home = get_home() / ".cache";
+      }
+    }
+    break;
+  }
+}
+
+}  // namespace
+
+void paths_to_read(Type type, std::string_view name,
+                   std::vector<std::filesystem::path>* out) {
+  std::string dirs;
+  std::filesystem::path home;
+  get_paths(type, &dirs, &home);
+  out->clear();
+  out->push_back(home / name);
+  size_t last = 0;
+  while (true) {
+    size_t next = dirs.find(':', last);
+    if (next == std::string::npos) {
+      if (valid(dirs, last, dirs.size() - last))
+        out->push_back(std::filesystem::path(dirs.substr(last)) / name);
+      break;
+    }
+    if (valid(dirs, last, next - last))
+      out->push_back(
+          std::filesystem::path(dirs.substr(last, next - last)) / name);
+    last = next + 1;
+  }
+}
+
+std::filesystem::path path_to_write(Type type, std::string_view name) {
+  std::filesystem::path home;
+  get_paths(type, nullptr, &home);
+  return home / name;
+}
+
+}  // namespace xdg