make get message consistent with rfc

include/stumpless/entry.h

@@ -592,6 +592,10 @@ stumpless_get_entry_hostname( const struct stumpless_entry *entry );
  * Note that if this message was originally set using format specifiers, the
  * result will have them substituted, instead of the original placeholders.
  *
+ * It is also important to note that the message may be NULL if the entry
+ * does not have one. This differs from other fields like the app id or msgid,
+ * which will be an RFC 5424 NILVALUE '-' if they have not been set.
+ *
  * In versions prior to v2.0.0, the returned pointer was to the internal buffer
  * used to store the name and was not to be modified by the caller. This
  * behavior changed in v2.0.0 in order to avoid thread safety issues.
@@ -614,9 +618,8 @@ stumpless_get_entry_hostname( const struct stumpless_entry *entry );
  *
  * @param entry The entry to get the message of.
  *
- * @return The message of the entry if no error is encountered. If an error
- * was encountered, then NULL is returned and an error code is set
- * appropriately.
+ * @return The message of the entry (which may be NULL). If an error was
+ * encountered, then NULL is returned and an error code is set appropriately.
  */
 STUMPLESS_PUBLIC_FUNCTION
 const char *

src/entry.c

@@ -412,13 +412,8 @@ stumpless_get_entry_message( const struct stumpless_entry *entry ) {
   VALIDATE_ARG_NOT_NULL( entry );
 
   lock_entry( entry );
-  if( entry->message_length == 0 ) {
-    message_copy = alloc_mem( 2 );
-    if( !message_copy ) {
-      goto cleanup_and_return;
-    }
-    message_copy[0] = '-';
-    message_copy[1] = '\0';
+  if( !entry->message ) {
+    message_copy = NULL;
   } else {
     message_copy = alloc_mem( entry->message_length + 1 );
     if( !message_copy ) {

src/target/sqlite3.c

@@ -382,10 +382,10 @@ stumpless_sqlite3_prepare( const struct stumpless_entry *entry,
   }
 
   if( message_index != 0 ) {
-    if( entry->message_length == 1 && entry->message[0] == '-' ) {
-      sql_result = sqlite3_bind_null( insert_stmt, message_index );
-    } else {
+    if( entry->message ) {
       sql_result = sqlite3_bind_text( insert_stmt, message_index, entry->message, entry->message_length, SQLITE_STATIC );
+    } else {
+      sql_result = sqlite3_bind_null( insert_stmt, message_index );
     }
     if( sql_result != SQLITE_OK ) {
       raise_sqlite3_error( "could not bind the message to the statement", sql_result ); // TODO l10n

test/function/entry.cpp

@@ -554,11 +554,8 @@ namespace {
     const char *message;
 
     message = stumpless_get_entry_message( nil_entry );
-    EXPECT_NOT_NULL( message );
+    EXPECT_NULL( message );
     EXPECT_NO_ERROR;
-
-    EXPECT_STREQ( message, "-" );
-    free( ( void * ) message );
   }
 
   TEST_F( EntryTest, GetParamByIndex ) {

test/function/target/sqlite3.cpp

@@ -104,18 +104,17 @@ TestEntryInDatabase( sqlite3 *db, std::string const &table_name, const struct st
                   "FROM " << table_name;
 
   expected_message = stumpless_get_entry_message( entry );
-  EXPECT_NOT_NULL( expected_message );
-  if( strcmp( expected_message, "-" ) == 0 ) {
-    query_stream << " WHERE message IS NULL";
-  } else {
+  if( expected_message ) {
     query_stream << " WHERE message = ?";
+  } else {
+    query_stream << " WHERE message IS NULL";
   }
   std::string result_query = query_stream.str();
 
   sql_result = sqlite3_prepare_v2( db, result_query.c_str(), -1, &result_stmt, NULL );
   EXPECT_EQ( sql_result, SQLITE_OK );
 
-  if( strcmp( expected_message, "-" ) != 0 ) {
+  if( expected_message ) {
     sql_result = sqlite3_bind_text( result_stmt,
                                     1,
                                     expected_message,