Use a different date time when normalizing zip entries

See also 584f9df.

PiperOrigin-RevId: 212574463

src/tools/singlejar/combiners.cc

@@ -67,8 +67,8 @@ void *Concatenator::OutputEntry(bool compress) {
   lh->signature();
   lh->version(20);
   lh->bit_flag(0x0);
-  lh->last_mod_file_time(1);   // 00:00:01
-  lh->last_mod_file_date(33);  // 1980-01-01
+  lh->last_mod_file_time(1);                     // 00:00:01
+  lh->last_mod_file_date(30 << 9 | 1 << 5 | 1);  // 2010-01-01
   lh->crc32(0x12345678);
   lh->compressed_file_size32(0);
   lh->file_name(filename_.c_str(), filename_.size());

src/tools/singlejar/output_jar.cc

@@ -298,6 +298,9 @@ bool OutputJar::Open() {
   return true;
 }
 
+// January 1, 2010 as a DOS date
+static const uint16_t kDefaultDate = 30 << 9 | 1 << 5 | 1;
+
 bool OutputJar::AddJar(int jar_path_index) {
   const std::string &input_jar_path =
       options_->input_jars[jar_path_index].first;
@@ -450,7 +453,7 @@ bool OutputJar::AddJar(int jar_path_index) {
     off64_t local_header_offset = Position();
 
     // When normalize_timestamps is set, entry's timestamp is to be set to
-    // 01/01/1980 00:00:00 (or to 01/01/1980 00:00:02, if an entry is a .class
+    // 01/01/2010 00:00:00 (or to 01/01/2010 00:00:02, if an entry is a .class
     // file). This is somewhat expensive because we have to copy the local
     // header to memory as input jar is memory mapped as read-only. Try to copy
     // as little as possible.
@@ -462,7 +465,7 @@ bool OutputJar::AddJar(int jar_path_index) {
         normalized_time = 1;
       }
       lh_field_to_remove = lh->unix_time_extra_field();
-      fix_timestamp = jar_entry->last_mod_file_date() != 33 ||
+      fix_timestamp = jar_entry->last_mod_file_date() != kDefaultDate ||
                       jar_entry->last_mod_file_time() != normalized_time ||
                       lh_field_to_remove != nullptr;
     }
@@ -489,7 +492,7 @@ bool OutputJar::AddJar(int jar_path_index) {
       } else {
         memcpy(lh_new, lh, lh_size);
       }
-      lh_new->last_mod_file_date(33);
+      lh_new->last_mod_file_date(kDefaultDate);
       lh_new->last_mod_file_time(normalized_time);
       // Now write these few bytes and adjust read/write positions accordingly.
       if (!WriteBytes(lh_new, lh_new->size())) {
@@ -549,9 +552,9 @@ void OutputJar::WriteEntry(void *buffer) {
   // https://msdn.microsoft.com/en-us/library/9kkf9tah.aspx
   // ("32-Bit Windows Time/Date Formats")
   if (options_->normalize_timestamps) {
-    // Regular "normalized" timestamp is 01/01/1980 00:00:00, while for the
-    // .class file it is 01/01/1980 00:00:02
-    entry->last_mod_file_date(33);
+    // Regular "normalized" timestamp is 01/01/2010 00:00:00, while for the
+    // .class file it is 01/01/2010 00:00:02
+    entry->last_mod_file_date(kDefaultDate);
     entry->last_mod_file_time(
         ends_with(entry->file_name(), entry->file_name_length(), ".class") ? 1
                                                                            : 0);
@@ -757,7 +760,7 @@ void OutputJar::AppendToDirectoryBuffer(const CDH *cdh, off64_t lh_pos,
   out_cdh->local_header_offset32(lh_pos_needs64 ? 0xFFFFFFFF : lh_pos);
   if (fix_timestamp) {
     out_cdh->last_mod_file_time(normalized_time);
-    out_cdh->last_mod_file_date(33);
+    out_cdh->last_mod_file_date(kDefaultDate);
   }
 }
 

src/tools/singlejar/output_jar_simple_test.cc

@@ -504,7 +504,7 @@ TEST_F(OutputJarSimpleTest, Normalize) {
                 "--classpath_resources", cp_resource_path});
 
   // Scan all entries, verify that *.class entries have timestamp
-  // 01/01/1980 00:00:02 and the rest have the timestamp of 01/01/1980 00:00:00.
+  // 01/01/2010 00:00:02 and the rest have the timestamp of 01/01/2010 00:00:00.
   InputJar input_jar;
   ASSERT_TRUE(input_jar.Open(out_path));
   const LH *lh;
@@ -515,8 +515,8 @@ TEST_F(OutputJarSimpleTest, Normalize) {
         << entry_name << " modification date";
     EXPECT_EQ(lh->last_mod_file_time(), cdh->last_mod_file_time())
         << entry_name << " modification time";
-    EXPECT_EQ(33, cdh->last_mod_file_date())
-        << entry_name << " modification date should be 01/01/1980";
+    EXPECT_EQ(15393, cdh->last_mod_file_date())
+        << entry_name << " modification date should be 01/01/2010";
     auto n = entry_name.size() - strlen(".class");
     if (0 == strcmp(entry_name.c_str() + n, ".class")) {
       EXPECT_EQ(1, cdh->last_mod_file_time())