Fix clear() call super antipattern in handlers

src/internfile/mh_exec.h

@@ -65,10 +65,9 @@ class MimeHandlerExec : public RecollFilter {
     virtual bool next_document();
     virtual bool skip_to_document(const std::string& ipath); 
 
-    virtual void clear() {
+    virtual void clear_impl() override {
 	m_fn.erase(); 
 	m_ipath.erase();
-	RecollFilter::clear(); 
     }
 
 protected:

src/internfile/mh_html.h

@@ -37,14 +37,12 @@ class MimeHandlerHtml : public RecollFilter {
 	return false;
     }
     virtual bool next_document();
-    const std::string& get_html() 
-    {
+    const std::string& get_html() {
 	return m_html;
     }
-    virtual void clear() {
+    virtual void clear_impl() override {
 	m_filename.erase();
 	m_html.erase();
-	RecollFilter::clear(); 
     }
 protected:
     virtual bool set_document_file_impl(const std::string& mt,

src/internfile/mh_mail.cpp

@@ -66,7 +66,7 @@ MimeHandlerMail::~MimeHandlerMail()
 {
     clear();
 }
-void MimeHandlerMail::clear()
+void MimeHandlerMail::clear_impl()
 {
     delete m_bincdoc; m_bincdoc = 0;
     if (m_fd >= 0) {
@@ -82,7 +82,6 @@ void MimeHandlerMail::clear()
 	delete *it;
     }
     m_attachments.clear();
-    RecollFilter::clear();
 }
 
 bool MimeHandlerMail::set_document_file_impl(const string& mt, const string &fn)

src/internfile/mh_mail.h

@@ -46,7 +46,7 @@ public:
     }
     virtual bool next_document();
     virtual bool skip_to_document(const std::string& ipath);
-    virtual void clear();
+    virtual void clear_impl() override;
 
 protected:
     virtual bool set_document_file_impl(const std::string& mt,

src/internfile/mh_mbox.cpp

@@ -232,7 +232,7 @@ MimeHandlerMbox::~MimeHandlerMbox()
     clear();
 }
 
-void MimeHandlerMbox::clear()
+void MimeHandlerMbox::clear_impl()
 {
     m_fn.erase();
     if (m_vfp) {
@@ -242,7 +242,6 @@ void MimeHandlerMbox::clear()
     m_msgnum =  m_lineno = 0;
     m_ipath.erase();
     m_offsets.clear();
-    RecollFilter::clear();
 }
 
 bool MimeHandlerMbox::set_document_file_impl(const string& mt, const string &fn)

src/internfile/mh_mbox.h

@@ -39,7 +39,7 @@ public:
 	m_ipath = ipath;
 	return true;
     }
-    virtual void clear();
+    virtual void clear_impl() override;
     typedef long long mbhoff_type;
 
 protected:

src/internfile/mh_text.h

@@ -43,12 +43,11 @@ class MimeHandlerText : public RecollFilter {
     }
     virtual bool next_document();
     virtual bool skip_to_document(const std::string& s);
-    virtual void clear() {
+    virtual void clear_impl() override {
         m_paging = false;
 	m_text.erase(); 
         m_fn.erase();
         m_offs = 0;
-	RecollFilter::clear();
     }
     
 protected:

src/internfile/mimehandler.h

@@ -115,15 +115,17 @@ public:
 	return m_id;
     }
 
-    // "Call super" anti-pattern again. Must be called from derived
-    // classes which reimplement clear()
-    virtual void clear() {
+    // Classes which need to do local work in clear() need
+    // to implement clear_impl()
+    virtual void clear() final {
+        clear_impl();
 	Dijon::Filter::clear();
 	m_forPreview = m_havedoc = false;
 	m_dfltInputCharset.clear();
 	m_reason.clear();
     }
-
+    virtual void clear_impl() {}
+    
     // This only makes sense if the contents are currently txt/plain
     // It converts from keyorigcharset to UTF-8 and sets keycharset.
     bool txtdcode(const std::string& who);