[res] Better modification time resolution in Idmap

We used to track the modification time in seconds, which is both
imprecise (an apk installation + idmap generation can easily
take less time) and forces us to wait for >1s in the tests to
just check if up-to-date checks work.

This change updates the time to nanosecond resolution where
supported (hm, MinGW for Windows, hm), as the underlying
OS API provides

Test: build + atest libandroidfw_tests idmap2_tests + boot
Flag: EXEMPT minor change
Change-Id: I37635e6f3b62aff3b4794912ac585a9ef5ea7a1e

1 files changed, 33 insertions, 22 deletions

diff --git a/libs/androidfw/misc.cpp b/libs/androidfw/misc.cpp
index 93dcaf549a90..9bdaf18a116a 100644
--- a/libs/androidfw/misc.cpp
+++ b/libs/androidfw/misc.cpp
@@ -28,11 +28,13 @@
 #include <sys/vfs.h>
 #endif  // __linux__
 
-#include <cstring>
-#include <cstdio>
 #include <errno.h>
 #include <sys/stat.h>
 
+#include <cstdio>
+#include <cstring>
+#include <tuple>
+
 namespace android {
 
 /*
@@ -73,27 +75,32 @@ FileType getFileType(const char* fileName)
     }
 }
 
-/*
- * Get a file's modification date.
- */
-time_t getFileModDate(const char* fileName) {
-    struct stat sb;
-    if (stat(fileName, &sb) < 0) {
-        return (time_t)-1;
-    }
-    return sb.st_mtime;
+static ModDate getModDate(const struct stat& st) {
+#ifdef _WIN32
+  return st.st_mtime;
+#else
+  return st.st_mtim;
+#endif
 }
 
-time_t getFileModDate(int fd) {
-    struct stat sb;
-    if (fstat(fd, &sb) < 0) {
-        return (time_t)-1;
-    }
-    if (sb.st_nlink <= 0) {
-        errno = ENOENT;
-        return (time_t)-1;
-    }
-    return sb.st_mtime;
+ModDate getFileModDate(const char* fileName) {
+  struct stat sb;
+  if (stat(fileName, &sb) < 0) {
+    return kInvalidModDate;
+  }
+  return getModDate(sb);
+}
+
+ModDate getFileModDate(int fd) {
+  struct stat sb;
+  if (fstat(fd, &sb) < 0) {
+    return kInvalidModDate;
+  }
+  if (sb.st_nlink <= 0) {
+    errno = ENOENT;
+    return kInvalidModDate;
+  }
+  return getModDate(sb);
 }
 
 #ifndef __linux__
@@ -124,4 +131,8 @@ bool isReadonlyFilesystem(int fd) {
 }
 #endif  // __linux__
 
-}; // namespace android
+}  // namespace android
+
+bool operator==(const timespec& l, const timespec& r) {
+  return std::tie(l.tv_sec, l.tv_nsec) == std::tie(r.tv_sec, l.tv_nsec);
+}