+ move 'bind' logic from datasource level to layer

+ store and copy mapnik::parameters only in mapnik::layer
+ make datasource_ptr mutable

include/mapnik/datasource.hpp

@@ -81,47 +81,25 @@ public:
         Collection = 4
     };
 
-    datasource (parameters const& params)
+    datasource (parameters const& params) {}
-        : params_(params),
+    
-        is_bound_(false)
-        {}
-
-    /*!
-     * @brief Get the configuration parameters of the data source.
-     *
-     * These vary depending on the type of data source.
-     *
-     * @return The configuration parameters of the data source.
-     */
-    parameters const& params() const
-    {
-        return params_;
-    }
-
     /*!
      * @brief Get the type of the datasource
      * @return The type of the datasource (Vector or Raster)
      */
     virtual datasource_t type() const=0;
-
+    virtual featureset_ptr features(query const& q) const=0;
-    /*!
-     * @brief Connect to the datasource
-     */
-    virtual void bind() const {};
-
-    virtual featureset_ptr features(const query& q) const=0;
     virtual featureset_ptr features_at_point(coord2d const& pt) const=0;
     virtual box2d<double> envelope() const=0;
     virtual boost::optional<geometry_t> get_geometry_type() const=0;
     virtual layer_descriptor get_descriptor() const=0;
     virtual ~datasource() {};
-protected:
-    parameters params_;
-    mutable bool is_bound_;
 };
 
+typedef boost::shared_ptr<datasource> datasource_ptr;
+
 typedef std::string datasource_name();
-typedef datasource* create_ds(const parameters& params, bool bind);
+typedef datasource* create_ds(parameters const& params);
 typedef void destroy_ds(datasource *ds);
 
 
@@ -134,17 +112,14 @@ public:
     }
 };
 
-typedef boost::shared_ptr<datasource> datasource_ptr;
-
-
 #define DATASOURCE_PLUGIN(classname)                                    \
     extern "C" MAPNIK_EXP std::string datasource_name()                 \
     {                                                                   \
         return classname::name();                                       \
     }                                                                   \
-    extern "C"  MAPNIK_EXP datasource* create(const parameters &params, bool bind) \
+    extern "C"  MAPNIK_EXP datasource* create(parameters const& params) \
     {                                                                   \
-        return new classname(params, bind);                             \
+        return new classname(params);                             \
     }                                                                   \
     extern "C" MAPNIK_EXP void destroy(datasource *ds)                  \
     {                                                                   \

include/mapnik/datasource_cache.hpp

@@ -37,6 +37,9 @@
 #include <map>
 
 namespace mapnik {
+
+class datasource;
+
 class MAPNIK_DECL datasource_cache :
         public singleton <datasource_cache,CreateStatic>,
         private boost::noncopyable
@@ -55,7 +58,8 @@ public:
     static std::vector<std::string> plugin_names();
     static std::string plugin_directories();
     static void register_datasources(const std::string& path);
-    static boost::shared_ptr<datasource> create(parameters const& params, bool bind=true);
+    
+    static boost::shared_ptr<datasource> create(parameters const& params);
 };
 }
 

include/mapnik/layer.hpp

@@ -176,13 +176,15 @@ public:
      *
      * @param ds The datasource to attach.
      */
-    void set_datasource(datasource_ptr const& ds);
+    void set_datasource_parameters(parameters const& p);
-
+    
+    parameters const& datasource_parameters() const;
+    
     /*!
      * @return the datasource attached to this layer.
      */
     datasource_ptr datasource() const;
-
+    
     /*!
      * @return the geographic envelope/bounding box of the data in the layer.
      */
@@ -203,7 +205,8 @@ private:
     bool cache_features_;
     std::string group_by_;
     std::vector<std::string>  styles_;
-    datasource_ptr ds_;
+    parameters datasource_params_;
+    mutable datasource_ptr ds_;
 };
 }
 

src/datasource_cache.cpp

@@ -62,7 +62,7 @@ std::map<std::string,boost::shared_ptr<PluginInfo> > datasource_cache::plugins_;
 bool datasource_cache::registered_=false;
 std::vector<std::string> datasource_cache::plugin_directories_;
 
-datasource_ptr datasource_cache::create(const parameters& params, bool bind)
+datasource_ptr datasource_cache::create(const parameters& params)
 {
     boost::optional<std::string> type = params.get<std::string>("type");
     if ( ! type)
@@ -106,7 +106,7 @@ datasource_ptr datasource_cache::create(const parameters& params, bool bind)
         std::clog << i->first << "=" << i->second << "\n";
     }
 #endif
-    ds=datasource_ptr(create_datasource(params, bind), datasource_deleter());
+    ds=datasource_ptr(create_datasource(params), datasource_deleter());
 
 #ifdef MAPNIK_DEBUG
     std::clog<<"datasource="<<ds<<" type="<<type<<std::endl;

src/deepcopy.cpp

@@ -96,18 +96,6 @@ namespace mapnik { namespace util {
         BOOST_FOREACH ( layer const& lyr_in, map_in.layers())
         {
             layer lyr_out(lyr_in);
-            datasource_ptr ds_in = lyr_in.datasource();
-            if (ds_in)
-            {
-                parameters p(ds_in->params());
-
-                // TODO : re-use datasource extent if already set.
-                datasource_ptr ds_out = datasource_cache::create(p);
-                if (ds_out)
-                {
-                    lyr_out.set_datasource(ds_out);
-                }
-            }
             map_out.addLayer(lyr_out);
         }
         typedef std::map<std::string, feature_type_style> style_cont;
@@ -120,7 +108,6 @@ namespace mapnik { namespace util {
             feature_type_style style_out(style_in,true); // deep copy
             map_out.insert_style(kv.first, style_out);
         }
-
     }
 
-    }}
+}}

src/layer.cpp

@@ -45,7 +45,7 @@ layer::layer(std::string const& name, std::string const& srs)
       clear_label_cache_(false),
       cache_features_(false),
       group_by_(""),
-      ds_() {}
+      datasource_params_() {}
 
 layer::layer(const layer& rhs)
     : name_(rhs.name_),
@@ -58,7 +58,7 @@ layer::layer(const layer& rhs)
       cache_features_(rhs.cache_features_),
       group_by_(rhs.group_by_),
       styles_(rhs.styles_),
-      ds_(rhs.ds_) {}
+      datasource_params_(rhs.datasource_params_) {}
 
 layer& layer::operator=(const layer& rhs)
 {
@@ -84,7 +84,7 @@ void layer::swap(const layer& rhs)
     cache_features_ = rhs.cache_features_;
     group_by_ = rhs.group_by_;
     styles_=rhs.styles_;
-    ds_=rhs.ds_;
+    datasource_params_ = rhs.datasource_params_;
 }
 
 layer::~layer() {}
@@ -171,17 +171,38 @@ bool layer::isQueryable() const
 
 datasource_ptr layer::datasource() const
 {
+    if (ds_) return ds_;
+    try
+    {
+        ds_ = datasource_cache::instance()->create(datasource_params_);
+    }
+    catch (const std::exception & ex )
+    {
+        throw config_error( ex.what() );
+    }
+    
+    catch (...)
+    {
+        throw config_error("Unknown exception occured attempting to create datasoure for layer '" + name_ + "'");
+    }
+    
     return ds_;
 }
 
-void layer::set_datasource(datasource_ptr const& ds)
+void layer::set_datasource_parameters(parameters const& p)
 {
-    ds_ = ds;
+    datasource_params_ = p;
+}
+
+parameters const& layer::datasource_parameters() const
+{
+    return datasource_params_;
 }
 
 box2d<double> layer::envelope() const
 {
-    if (ds_) return ds_->envelope();
+    datasource_ptr ds = this->datasource();
+    if (ds) return ds->envelope();
     return box2d<double>();
 }