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);
+}

src/common/io.h

@@ -291,3 +291,7 @@ static inline void wrapClosedir(HANDLE* pdir) {
 
 FFNativeFD ffGetNullFD(void);
 bool ffRemoveFile(const char* fileName);
+// Modification time of a file, in milliseconds since the Unix epoch, or 0 if it can not be read.
+// The representation is uniform across platforms so that a value derived from it means the
+// same thing everywhere, which matters for callers that store it as a cache key.
+[[gnu::nonnull(1)]] uint64_t ffPathGetMtime(const char* path);

src/detection/packages/packages.c

@@ -1,14 +1,9 @@
 #include "packages.h"
 #include "common/io.h"
-#include "common/time.h"
 
 #include <inttypes.h>
 #include <stddef.h>
 
-#ifdef __APPLE__
-    #define st_mtim st_mtimespec
-#endif
-
 void ffDetectPackagesImpl(FFPackagesResult* result, FFPackagesOptions* options);
 
 const char* ffDetectPackages(FFPackagesResult* result, FFPackagesOptions* options) {
@@ -22,38 +17,20 @@ const char* ffDetectPackages(FFPackagesResult* result, FFPackagesOptions* option
 }
 
 bool ffPackagesReadCache(FFstrbuf* cacheDir, FFstrbuf* cacheContent, const char* filePath, const char* packageId, uint32_t* result) {
-#ifndef _WIN32
-    struct stat st;
-    if (stat(filePath, &st) < 0) // file doesn't exist or isn't accessible
-    {
+    const uint64_t mtime_current = ffPathGetMtime(filePath);
+    if (__builtin_expect(mtime_current == 0, false)) {
+        // A missing database legitimately means "no packages installed", and must not be cached.
+        // A database whose modification time could not be read must not be cached either, and
+        // reporting 0 for it would be a lie. ffPathGetMtime() reports 0 for both, so tell them
+        // apart before deciding which of the two applies.
+        if (ffPathExists(filePath, FF_PATHTYPE_FILE)) {
+            return false;
+        }
+
         *result = 0;
         return true;
     }
 
-    if (__builtin_expect(st.st_mtim.tv_sec <= 0, false)) {
-        return false;
-    }
-
-    uint64_t mtime_current = (uint64_t) st.st_mtim.tv_sec * 1000ull + (uint64_t) st.st_mtim.tv_nsec / 1000000ull;
-#else
-    FF_AUTO_CLOSE_FD HANDLE handle = CreateFileA(filePath, 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
-    {
-        *result = 0;
-        return true;
-    }
-
-    uint64_t mtime_current;
-    FILE_BASIC_INFORMATION fileInfo;
-    IO_STATUS_BLOCK iosb;
-    if (!NT_SUCCESS(NtQueryInformationFile(handle, &iosb, &fileInfo, sizeof(fileInfo), FileBasicInformation))) {
-        return false;
-    }
-
-    mtime_current = ffFileTimeToUnixMs((uint64_t) fileInfo.LastWriteTime.QuadPart);
-#endif
-
     ffStrbufSet(cacheDir, &instance.state.platform.cacheDir);
     ffStrbufEnsureEndsWithC(cacheDir, '/');
     ffStrbufAppendF(cacheDir, "fastfetch/packages/%s.txt", packageId);