AK: Avoid returning null StringViews instead of empty views

This was error-prone and most users were just checking the length anyway

(cherry picked from commit 57ba720fb184ddf59fb09d3290e07cd425be450e)

AK/GenericLexer.cpp

@@ -19,9 +19,6 @@ namespace AK {
 // Consume a number of characters
 StringView GenericLexer::consume(size_t count)
 {
-    if (count == 0)
-        return {};
-
     size_t start = m_index;
     size_t length = min(count, m_input.length() - m_index);
     m_index += length;
@@ -32,9 +29,6 @@ StringView GenericLexer::consume(size_t count)
 // Consume the rest of the input
 StringView GenericLexer::consume_all()
 {
-    if (is_eof())
-        return {};
-
     auto rest = m_input.substring_view(m_index, m_input.length() - m_index);
     m_index = m_input.length();
     return rest;
@@ -51,8 +45,6 @@ StringView GenericLexer::consume_line()
     consume_specific('\r');
     consume_specific('\n');
 
-    if (length == 0)
-        return {};
     return m_input.substring_view(start, length);
 }
 
@@ -64,8 +56,6 @@ StringView GenericLexer::consume_until(char stop)
         m_index++;
     size_t length = m_index - start;
 
-    if (length == 0)
-        return {};
     return m_input.substring_view(start, length);
 }
 
@@ -77,8 +67,6 @@ StringView GenericLexer::consume_until(char const* stop)
         m_index++;
     size_t length = m_index - start;
 
-    if (length == 0)
-        return {};
     return m_input.substring_view(start, length);
 }
 
@@ -90,8 +78,6 @@ StringView GenericLexer::consume_until(StringView stop)
         m_index++;
     size_t length = m_index - start;
 
-    if (length == 0)
-        return {};
     return m_input.substring_view(start, length);
 }
 

AK/GenericLexer.h

@@ -190,8 +190,6 @@ public:
             ++m_index;
         size_t length = m_index - start;
 
-        if (length == 0)
-            return {};
         return m_input.substring_view(start, length);
     }
 
@@ -204,8 +202,6 @@ public:
             ++m_index;
         size_t length = m_index - start;
 
-        if (length == 0)
-            return {};
         return m_input.substring_view(start, length);
     }