Fixed manifest_dump issues when printing keys and values containing null characters (#8378)

Summary:
Changed fprintf function to fputc in ApplyVersionEdit, and replaced null characters with whitespaces.
Added unit test in ldb_test.py - verifies that manifest_dump --verbose output is correct when keys and values containing null characters are inserted.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8378

Reviewed By: pdillinger

Differential Revision: D29034584

Pulled By: bjlemaire

fbshipit-source-id: 50833687a8a5f726e247c38457eadc3e6dbab862

db/version_edit_handler.cc

@@ -909,7 +909,10 @@ void DumpManifestHandler::CheckIterationResult(const log::Reader& reader,
       fprintf(stdout, "comparator: %s\n", cfd->user_comparator()->Name());
     }
     assert(cfd->current());
-    fprintf(stdout, "%s \n", cfd->current()->DebugString(hex_).c_str());
+
+    // Print out DebugStrings. Can include non-terminating null characters.
+    fwrite(cfd->current()->DebugString(hex_).data(), sizeof(char),
+           cfd->current()->DebugString(hex_).size(), stdout);
   }
   fprintf(stdout,
           "next_file_number %" PRIu64 " last_sequence %" PRIu64

db/version_edit_handler.h

@@ -285,9 +285,13 @@ class DumpManifestHandler : public VersionEditHandler {
   Status ApplyVersionEdit(VersionEdit& edit, ColumnFamilyData** cfd) override {
     // Write out each individual edit
     if (verbose_ && !json_) {
-      fprintf(stdout, "%s\n", edit.DebugString(hex_).c_str());
+      // Print out DebugStrings. Can include non-terminating null characters.
+      fwrite(edit.DebugString(hex_).data(), sizeof(char),
+             edit.DebugString(hex_).size(), stdout);
     } else if (json_) {
-      fprintf(stdout, "%s\n", edit.DebugJSON(count_, hex_).c_str());
+      // Print out DebugStrings. Can include non-terminating null characters.
+      fwrite(edit.DebugString(hex_).data(), sizeof(char),
+             edit.DebugString(hex_).size(), stdout);
     }
     ++count_;
     return VersionEditHandler::ApplyVersionEdit(edit, cfd);

tools/ldb_test.py

@@ -473,6 +473,31 @@ class LDBTestCase(unittest.TestCase):
                              expected_pattern, unexpected=False,
                              isPattern=True)
 
+        # Check if null characters doesn't infer with output format.
+        self.assertRunOK("put a1 b1", "OK")
+        self.assertRunOK("put a2 b2", "OK")
+        self.assertRunOK("put --hex 0x12000DA0 0x80C0000B", "OK")
+        self.assertRunOK("put --hex 0x7200004f 0x80000004", "OK")
+        self.assertRunOK("put --hex 0xa000000a 0xf000000f", "OK")
+        self.assertRunOK("put a3 b3", "OK")
+        self.assertRunOK("put a4 b4", "OK")
+
+        # Verifies that all "levels" are printed out.
+        # There should be 66 mentions of levels.
+        expected_verbose_output = re.compile("matched")
+        # Test manifest_dump verbose and verify that key 0x7200004f
+        # is present. Note that we are forced to use grep here because
+        # an output with a non-terminating null character in it isn't piped
+        # correctly through the Python subprocess object.
+        # Also note that 0x72=r and 0x4f=O, hence the regex \'r.{2}O\'
+        # (we cannot use null character in the subprocess input either,
+        # so we have to use '.{2}')
+        cmd_verbose = "manifest_dump --verbose --db=%s | grep -aq $'\'r.{2}O\'' && echo 'matched' || echo 'not matched'" %dbPath
+
+        self.assertRunOKFull(cmd_verbose , expected_verbose_output,
+                             unexpected=False, isPattern=True)
+
+
     def testGetProperty(self):
         print("Running testGetProperty...")
         dbPath = os.path.join(self.TMP_DIR, self.DB_NAME)