From a6e24513d89067c16a3df214a7e2679e1f1675f1 Mon Sep 17 00:00:00 2001
From: Boris Kolpackov <boris@codesynthesis.com>
Date: Thu, 8 May 2014 17:02:55 -0700
Subject: Add helpers for parsing elements with simple content

---
 tests/parser/driver.cxx | 58 +++++++++++++++++++++++++++++++++++++++++++++++++
 xml/parser.cxx          | 36 ++++++++++++++++++++++++++++++
 xml/parser.hxx          | 56 ++++++++++++++++++++++++++++++++++++++++++-----
 xml/parser.ixx          | 48 ++++++++++++++++++++++++++++++++++++++++
 xml/parser.txx          | 13 +++++++++++
 5 files changed, 206 insertions(+), 5 deletions(-)

diff --git a/tests/parser/driver.cxx b/tests/parser/driver.cxx
index a8230cd..84ab2fa 100644
--- a/tests/parser/driver.cxx
+++ b/tests/parser/driver.cxx
@@ -391,6 +391,64 @@ main ()
     // cerr << e.what () << endl;
   }
 
+  // Test element with simple content helpers.
+  //
+  {
+    istringstream is ("<root>"
+                      "  <nested>X</nested>"
+                      "  <nested/>"
+                      "  <nested>123</nested>"
+                      "  <nested>Y</nested>"
+                      "  <t:nested xmlns:t='test'>Z</t:nested>"
+                      "  <nested>234</nested>"
+                      "  <t:nested xmlns:t='test'>345</t:nested>"
+                      "  <nested>A</nested>"
+                      "  <t:nested xmlns:t='test'>B</t:nested>"
+                      "  <nested1>A</nested1>"
+                      "  <t:nested1 xmlns:t='test'>B</t:nested1>"
+                      "  <nested>1</nested>"
+                      "  <t:nested xmlns:t='test'>2</t:nested>"
+                      "  <nested1>1</nested1>"
+                      "  <t:nested1 xmlns:t='test'>2</t:nested1>"
+                      "</root>");
+    parser p (is, "element");
+
+    p.next_expect (parser::start_element, "root", parser::complex);
+
+    p.next_expect (parser::start_element, "nested");
+    assert (p.element () == "X");
+
+    p.next_expect (parser::start_element, "nested");
+    assert (p.element () == "");
+
+    p.next_expect (parser::start_element, "nested");
+    assert (p.element<unsigned int> () == 123);
+
+    assert (p.element ("nested") == "Y");
+    assert (p.element (qname ("test", "nested")) == "Z");
+
+    assert (p.element<unsigned int> ("nested") == 234);
+    assert (p.element<unsigned int> (qname ("test", "nested")) == 345);
+
+    assert (p.element ("nested", "a") == "A");
+    assert (p.element (qname ("test", "nested"), "b") == "B");
+
+    assert (p.element ("nested", "a") == "a" &&
+            p.element ("nested1") == "A");
+    assert (p.element (qname ("test", "nested"), "b") == "b" &&
+            p.element (qname ("test", "nested1")) == "B");
+
+    assert (p.element<unsigned int> ("nested", 10) == 1);
+    assert (p.element<unsigned int> (qname ("test", "nested"), 20) == 2);
+
+    assert (p.element<unsigned int> ("nested", 10) == 10 &&
+            p.element<unsigned int> ("nested1") == 1);
+    assert (p.element<unsigned int> (qname ("test", "nested"), 20) == 20 &&
+            p.element<unsigned int> (qname ("test", "nested1")) == 2);
+
+    p.next_expect (parser::end_element);
+  }
+
   // Test the iterator interface.
   //
   {
diff --git a/xml/parser.cxx b/xml/parser.cxx
index d9d2fcb..6d5ab23 100644
--- a/xml/parser.cxx
+++ b/xml/parser.cxx
@@ -283,6 +283,42 @@ namespace xml
                      qname_type (ns, n).string () + "' expected");
   }
 
+  string parser::
+  element ()
+  {
+    content (simple);
+    string r;
+
+    // The content of the element can be empty in which case there
+    // will be no characters event.
+    //
+    event_type e (next ());
+    if (e == characters)
+    {
+      r.swap (value ());
+      e = next ();
+    }
+
+    // We cannot really get anything other than end_element since
+    // the simple content validation won't allow it.
+    //
+    assert (e == end_element);
+
+    return r;
+  }
+
+  string parser::
+  element (const qname_type& qn, const string& dv)
+  {
+    if (peek () == start_element && qname () == qn)
+    {
+      next ();
+      return element ();
+    }
+
+    return dv;
+  }
+
   const parser::element_entry* parser::
   get_element_ () const
   {
diff --git a/xml/parser.hxx b/xml/parser.hxx
index 51d589e..7c2cc45 100644
--- a/xml/parser.hxx
+++ b/xml/parser.hxx
@@ -219,6 +219,7 @@ namespace xml
     const std::string& name () const {return pqname_->name ();}
     const std::string& prefix () const {return pqname_->prefix ();}
 
+    std::string& value () {return *pvalue_;}
     const std::string& value () const {return *pvalue_;}
     template <typename T> T value () const;
 
@@ -246,11 +247,12 @@ namespace xml
     attribute (const std::string& name) const;
 
     std::string
-    attribute (const std::string& name, const std::string& dv) const;
+    attribute (const std::string& name,
+               const std::string& default_value) const;
 
     template <typename T>
     T
-    attribute (const std::string& name, const T& dv) const;
+    attribute (const std::string& name, const T& default_value) const;
 
     const std::string&
     attribute (const qname_type& qname) const;
@@ -260,11 +262,12 @@ namespace xml
     attribute (const qname_type& qname) const;
 
     std::string
-    attribute (const qname_type& qname, const std::string& dv) const;
+    attribute (const qname_type& qname,
+               const std::string& default_value) const;
 
     template <typename T>
     T
-    attribute (const qname_type& qname, const T& dv) const;
+    attribute (const qname_type& qname, const T& default_value) const;
 
     bool
     attribute_present (const std::string& name) const;
@@ -337,6 +340,49 @@ namespace xml
                  const std::string& ns, const std::string& name,
                  content_type);
 
+    // Helpers for parsing elements with simple content. The first two
+    // functions assume that start_element has already been parsed. The
+    // rest parse the complete element, from start to end.
+    //
+    // Note also that as with attribute(), there is no (namespace,name)
+    // overload since it would conflicts with (namespace,default_value).
+    //
+  public:
+    std::string
+    element ();
+
+    template <typename T>
+    T
+    element ();
+
+    std::string
+    element (const std::string& name);
+
+    std::string
+    element (const qname_type& qname);
+
+    template <typename T>
+    T
+    element (const std::string& name);
+
+    template <typename T>
+    T
+    element (const qname_type& qname);
+
+    std::string
+    element (const std::string& name, const std::string& default_value);
+
+    std::string
+    element (const qname_type& qname, const std::string& default_value);
+
+    template <typename T>
+    T
+    element (const std::string& name, const T& default_value);
+
+    template <typename T>
+    T
+    element (const qname_type& qname, const T& default_value);
+
     // C++11 range-based for support. Generally, the iterator interface
     // doesn't make much sense for the parser so for now we have an
     // implementation that is just enough to the range-based for.
@@ -420,7 +466,7 @@ namespace xml
     // and namespace decls.
     //
     const qname_type* pqname_;
-    const std::string* pvalue_;
+    std::string* pvalue_;
 
     unsigned long long line_;
     unsigned long long column_;
diff --git a/xml/parser.ixx b/xml/parser.ixx
index e58d2cf..c0fe256 100644
--- a/xml/parser.ixx
+++ b/xml/parser.ixx
@@ -125,6 +125,54 @@ namespace xml
     content (c);
   }
 
+  template <typename T>
+  inline T parser::
+  element ()
+  {
+    return value_traits<T>::parse (element (), *this);
+  }
+
+  inline std::string parser::
+  element (const std::string& n)
+  {
+    next_expect (start_element, n);
+    return element ();
+  }
+
+  inline std::string parser::
+  element (const qname_type& qn)
+  {
+    next_expect (start_element, qn);
+    return element ();
+  }
+
+  template <typename T>
+  inline T parser::
+  element (const std::string& n)
+  {
+    return value_traits<T>::parse (element (n), *this);
+  }
+
+  template <typename T>
+  inline T parser::
+  element (const qname_type& qn)
+  {
+    return value_traits<T>::parse (element (qn), *this);
+  }
+
+  inline std::string parser::
+  element (const std::string& n, const std::string& dv)
+  {
+    return element (qname_type (n), dv);
+  }
+
+  template <typename T>
+  inline T parser::
+  element (const std::string& n, const T& dv)
+  {
+    return element<T> (qname_type (n), dv);
+  }
+
   inline const parser::element_entry* parser::
   get_element () const
   {
diff --git a/xml/parser.txx b/xml/parser.txx
index e882c82..0167522 100644
--- a/xml/parser.txx
+++ b/xml/parser.txx
@@ -27,4 +27,17 @@ namespace xml
 
     return dv;
   }
+
+  template <typename T>
+  T parser::
+  element (const qname_type& qn, const T& dv)
+  {
+    if (peek () == start_element && qname () == qn)
+    {
+      next ();
+      return element<T> ();
+    }
+
+    return dv;
+  }
 }
-- 
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