Improve iostr::forEachLine to accept lamdas, add simpleParseFile

diff --git a/zypp/base/IOStream.cc b/zypp/base/IOStream.cc
index 0bb5b77..cd22598 100644 (file)
--- a/zypp/base/IOStream.cc
+++ b/zypp/base/IOStream.cc
@@ -10,12 +10,14 @@
  *
 */
 #include <iostream>
+#include <boost/mpl/assert.hpp>
+#include <boost/mpl/int.hpp>
 //#include "zypp/base/Logger.h"
 
 #include "zypp/base/IOStream.h"
+#include "zypp/base/String.h"
 
 using std::endl;
-
 ///////////////////////////////////////////////////////////////////
 namespace zypp
 { /////////////////////////////////////////////////////////////////
@@ -91,6 +93,63 @@ namespace zypp
       return(_valid = true);
     }
 
+    ///////////////////////////////////////////////////////////////////
+    // forEachLine
+    ///////////////////////////////////////////////////////////////////
+
+    int forEachLine( std::istream & str_r, function<bool(int, std::string)> consume_r )
+    {
+      int lineno = 0;
+      while ( str_r )
+      {
+       std::string line( getline( str_r ) );
+       if ( ! (str_r.fail() || str_r.bad()) )
+       {
+         // line contains valid data to be consumed.
+         ++lineno;
+         if ( consume_r && ! consume_r( lineno, line ) )
+         {
+           lineno = -lineno;
+           break;
+         }
+       }
+      }
+      return lineno;
+    }
+
+    // MPL checks to assert equal values for PF_?TRIM and str::?TRIM
+    BOOST_MPL_ASSERT_RELATION( int(PF_LTRIM), ==, int(str::L_TRIM) );
+    BOOST_MPL_ASSERT_RELATION( int(PF_RTRIM), ==, int(str::R_TRIM) );
+
+    int simpleParseFile( std::istream & str_r, ParseFlags flags_r, function<bool(int, std::string)> consume_r )
+    {
+      return forEachLine( str_r,
+                         [&]( int num_r, std::string line_r )->bool
+                         {
+                           if ( ! consume_r )
+                             return true;
+
+                           if ( flags_r )
+                           {
+                             if ( flags_r & PF_TRIM )
+                               line_r = str::trim( line_r, str::Trim( unsigned(flags_r & PF_TRIM) ) );
+
+                             if ( flags_r & ~PF_TRIM )
+                             {
+                               const char* firstNW = line_r.c_str();
+                               while ( *firstNW == ' ' || *firstNW == '\t' )
+                                 ++firstNW;
+                               switch ( *firstNW )
+                               {
+                                 case '\0':    if ( flags_r & PF_SKIP_EMPTY )          return true; break;
+                                 case '#':     if ( flags_r & PF_SKIP_SHARP_COMMENT )  return true; break;
+                               }
+                             }
+                           }
+                           return consume_r( num_r, line_r );
+                         } );
+    }
+
     /////////////////////////////////////////////////////////////////
   } // namespace iostr
   ///////////////////////////////////////////////////////////////////

diff --git a/zypp/base/IOStream.h b/zypp/base/IOStream.h
index d7b5749..70d6288 100644 (file)
--- a/zypp/base/IOStream.h
+++ b/zypp/base/IOStream.h
@@ -15,9 +15,11 @@
 #include <iosfwd>
 #include <boost/io/ios_state.hpp>
 
+#include "zypp/base/Flags.h"
 #include "zypp/base/PtrTypes.h"
-#include <zypp/base/SafeBool.h>
-#include <zypp/base/NonCopyable.h>
+#include "zypp/base/SafeBool.h"
+#include "zypp/base/Function.h"
+#include "zypp/base/NonCopyable.h"
 
 ///////////////////////////////////////////////////////////////////
 namespace zypp
@@ -171,40 +173,42 @@ namespace zypp
 
     /** Simple lineparser: Call functor \a consume_r for each line.
      *
-     * \param str_r The istream to read from.
-     * \param consume_r A reference to a function or functor. The loop is
-     * aborted if the function returns \c false.
-     * \code
-     * bool consume( const std::string & )
-     * { ... }
+     * \param str_r istream to read from.
+     * \param consume_r callback function taking linenumber and content
      *
-     * struct Consume : public std::unary_function<const std::string &, bool>
-     * {
-     *   bool operator()( const std::string & line_r )
-     *   { ... }
-     * };
-     * \endcode
+     * The loop is aborted if the callback  returns \c false.
      *
-     * \return A reference to \a consume_r.
+     * \code
+     *   iostr::forEachLine( InputStream( "/my/file/to/read.txt" ),
+     *                       []( int num_r, std::string line_r )->bool
+     *                       {
+     *                         MIL << " [" num_r << "]'" << line_r << "'" << endl;
+     *                         return true;
+     *                       } );
+     * \endcode
      *
-     * \todo Should be templated and specialized according to the
-     * functors return type, to allow \c void consumer.
+     * \return Number if lines consumed (negative if aborted by callback).
      */
-    template<class _Function>
-      _Function & forEachLine( std::istream & str_r, _Function & consume_r )
-      {
-        while ( str_r )
-          {
-            std::string l = getline( str_r );
-            if ( ! (str_r.fail() || str_r.bad()) )
-              {
-                // l contains valid data to be consumed.
-                if ( ! consume_r( l ) )
-                  break;
-              }
-          }
-        return consume_r;
-      }
+     int forEachLine( std::istream & str_r, function<bool(int, std::string)> consume_r );
+
+     /** \ref simpleParseFile modifications before consuming a line. */
+     enum ParseFlag
+     {
+       PF_LTRIM                        = 1 << 0,               //< left trim whitespace
+       PF_RTRIM                        = 1 << 1,               //< right trim whitespace
+       PF_TRIM                 = PF_LTRIM | PF_RTRIM,  //< trim whitespace
+       PF_SKIP_EMPTY           = 1 << 2,               //< skip lines containing whitespace only
+       PF_SKIP_SHARP_COMMENT   = 1 << 3                //< skip lines beginning with '#'
+     };
+     ZYPP_DECLARE_FLAGS( ParseFlags, ParseFlag );
+     ZYPP_DECLARE_OPERATORS_FOR_FLAGS( ParseFlags );
+
+     /** Simple lineparser optionally trimming and skipping comments. */
+     int simpleParseFile( std::istream & str_r, ParseFlags flags_r, function<bool(int, std::string)> consume_r );
+
+     /** \overload trimming lines, skipping '#'-comments and empty lines. */
+     inline int simpleParseFile( std::istream & str_r, function<bool(int, std::string)> consume_r )
+     { return simpleParseFile( str_r, PF_TRIM | PF_SKIP_EMPTY | PF_SKIP_SHARP_COMMENT , consume_r ); }
 
     /////////////////////////////////////////////////////////////////
   } // namespace iostr