Implement feed updates.

Author: wolfpld

src/Apod.cpp

@@ -23,7 +23,7 @@ bool Apod::InitializeImpl( ini_t* config )
     return status;
 }
 
-bool Apod::FetchImpl()
+bool Apod::FetchImpl( bool first )
 {
     auto page = FetchPage( "https://apod.nasa.gov/apod/astropix.html" );
     if( !PageHashChanged( page ) ) return true;
@@ -64,10 +64,14 @@ bool Apod::FetchImpl()
         {
             ProcessArticle( article, url.c_str(), timestamp );
         }
+        else if( !first )
+        {
+            return true;
+        }
 
         auto next = article->select_node( "//a[text()='<']" );
         if( !next ) return !m_articles.empty();
-        if( ++num == m_numArticles ) return true;
+        if( first && ++num == m_numArticles ) return true;
 
         url = m_baseUrl + next.node().attribute( "href" ).as_string();
         article = FetchDom( FetchPage( url.c_str() ) );

src/Apod.hpp

@@ -13,7 +13,7 @@ class Apod : public Handler
 
 private:
     bool InitializeImpl( ini_t* config ) final;
-    bool FetchImpl() final;
+    bool FetchImpl( bool first ) final;
 
     void ProcessArticle( const std::unique_ptr<pugi::xml_document>& article, const char* url, uint64_t timestamp );
 

src/Engine.cpp

@@ -1,5 +1,6 @@
 #include <atomic>
 #include <assert.h>
+#include <chrono>
 #include <signal.h>
 #include <sstream>
 #include <stdio.h>
@@ -87,9 +88,32 @@ bool Engine::Initialize( ini_t* config )
     printf( "Populating feeds\n" );
     for( auto& hnd : m_handlers )
     {
-        Enqueue( 0, [&hnd] {
-            hnd->Fetch();
-        } );
+        std::function<void()> FetchFunc, PopulateFunc;
+        FetchFunc = [&hnd, FetchFunc] {
+            const auto res = hnd->Fetch( false );
+            const auto ct = std::chrono::duration_cast<std::chrono::seconds>( std::chrono::steady_clock::now().time_since_epoch() ).count();
+            if( res )
+            {
+                Engine::Instance()->Enqueue( ct + hnd->GetRefresh(), FetchFunc );
+            }
+            else
+            {
+                Engine::Instance()->Enqueue( ct + hnd->GetFailureRefresh(), FetchFunc );
+            }
+        };
+        PopulateFunc = [&hnd, FetchFunc, PopulateFunc] {
+            const auto res = hnd->Fetch( true );
+            const auto ct = std::chrono::duration_cast<std::chrono::seconds>( std::chrono::steady_clock::now().time_since_epoch() ).count();
+            if( res )
+            {
+                Engine::Instance()->Enqueue( ct + hnd->GetRefresh(), FetchFunc );
+            }
+            else
+            {
+                Engine::Instance()->Enqueue( ct + hnd->GetFailureRefresh(), PopulateFunc );
+            }
+        };
+        Enqueue( 0, PopulateFunc );
     }
     return true;
 }

src/Engine.hpp

@@ -1,6 +1,7 @@
 #ifndef __ENGINE_HPP__
 #define __ENGINE_HPP__
 
+#include <functional>
 #include <memory>
 #include <vector>
 

src/Handler.cpp

@@ -48,16 +48,19 @@ bool Handler::Initialize( ini_t* config )
     return InitializeImpl( config );
 }
 
-bool Handler::Fetch()
+bool Handler::Fetch( bool first )
 {
-    const auto status = FetchImpl();
+    const auto status = FetchImpl( first );
     if( status )
     {
         SortArticles();
         TrimArticles();
         CacheFeed();
-        PrintStatus( true, "Fetch: %s (%i/%i articles)", GetTitle().c_str(), (int)m_articles.size(), m_numArticles );
-        m_ready.store( true, std::memory_order_release );
+        if( first )
+        {
+            PrintStatus( true, "Fetch: %s (%i/%i articles)", GetTitle().c_str(), (int)m_articles.size(), m_numArticles );
+            m_ready.store( true, std::memory_order_release );
+        }
     }
     else
     {

src/Handler.hpp

@@ -26,7 +26,7 @@ class Handler
     virtual ~Handler();
 
     bool Initialize( ini_t* config );
-    bool Fetch();
+    bool Fetch( bool first );
 
     const std::string& GetTitle() const { return m_title; }
     const std::string& GetDescription() const { return m_description; }
@@ -44,7 +44,7 @@ class Handler
 
 protected:
     virtual bool InitializeImpl( ini_t* config ) = 0;
-    virtual bool FetchImpl() = 0;
+    virtual bool FetchImpl( bool first ) = 0;
 
     std::vector<uint8_t> FetchPage( const char* url );
     bool PageHashChanged( const std::vector<uint8_t>& page );