Common (IO): adds ffPathGetMtime and uses it

src/common/impl/io_unix.c

@@ -11,6 +11,7 @@
     #include <poll.h>
 #else
     #include <sys/select.h>
+    #define st_mtim st_mtimespec // `struct stat` spells it `st_mtimespec` on Apple
 #endif
 
 #if FF_HAVE_WORDEXP
@@ -331,3 +332,18 @@ FFNativeFD ffGetNullFD(void) {
 bool ffRemoveFile(const char* fileName) {
     return unlink(fileName) == 0;
 }
+
+uint64_t ffPathGetMtime(const char* path) {
+    struct stat st;
+    if (stat(path, &st) != 0) {
+        return 0;
+    }
+
+    // An mtime at or before the Unix epoch means the filesystem did not fill it in. Reporting it
+    // as-is would hand the caller a value indistinguishable from "unknown", so treat it as such.
+    if (st.st_mtim.tv_sec <= 0) {
+        return 0;
+    }
+
+    return (uint64_t) st.st_mtim.tv_sec * 1000ull + (uint64_t) st.st_mtim.tv_nsec / 1000000ull;
+}

src/common/impl/io_windows.c

@@ -1,6 +1,7 @@
 #include "fastfetch.h"
 #include "common/io.h"
 #include "common/strutil.h"
+#include "common/time.h"
 #include "common/windows/nt.h"
 #include "common/windows/unicode.h"
 
@@ -499,3 +500,19 @@ FFNativeFD ffGetNullFD(void) {
 bool ffRemoveFile(const char* fileName) {
     return DeleteFileA(fileName) != FALSE;
 }
+
+uint64_t ffPathGetMtime(const char* path) {
+    FF_AUTO_CLOSE_FD HANDLE handle = CreateFileA(path, GENERIC_READ, FILE_SHARE_READ, nullptr, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, nullptr);
+
+    if (handle == INVALID_HANDLE_VALUE) { // file doesn't exist or isn't accessible
+        return 0;
+    }
+
+    FILE_BASIC_INFORMATION fileInfo;
+    IO_STATUS_BLOCK iosb;
+    if (!NT_SUCCESS(NtQueryInformationFile(handle, &iosb, &fileInfo, sizeof(fileInfo), FileBasicInformation))) {
+        return 0;
+    }
+
+    return ffFileTimeToUnixMs((uint64_t) fileInfo.LastWriteTime.QuadPart);
+}