Don't cache github libraries above nginx server.

It's too expensive to fetch the timestamps when the github
server is busy.  See Dick Hollenbeck's comments at the top of
github_plugin.cpp for more info.

Also adds some safety to the other caching algorithms after
seeing github_plugin's wild-west usage of the kicad_plugin.

Fixes: lp:1753143
* https://bugs.launchpad.net/kicad/+bug/1753143

common/fp_lib_table.cpp

@@ -241,7 +241,7 @@ long long FP_LIB_TABLE::GenerateTimestamp( const wxString* aNickname )
     {
         const FP_LIB_TABLE_ROW* row = FindRow( *aNickname );
         wxASSERT( (PLUGIN*) row->plugin );
-        return row->plugin->GetLibraryTimestamp();
+        return row->plugin->GetLibraryTimestamp( row->GetFullURI( true ) );
     }
 
     long long hash = 0;
@@ -250,7 +250,7 @@ long long FP_LIB_TABLE::GenerateTimestamp( const wxString* aNickname )
     {
         const FP_LIB_TABLE_ROW* row = FindRow( nickname );
         wxASSERT( (PLUGIN*) row->plugin );
-        hash += row->plugin->GetLibraryTimestamp();
+        hash += row->plugin->GetLibraryTimestamp( row->GetFullURI( true ) );
     }
 
     return hash;

pcbnew/eagle_plugin.h

@@ -98,9 +98,9 @@ public:
     MODULE* FootprintLoad( const wxString& aLibraryPath, const wxString& aFootprintName,
             const PROPERTIES* aProperties = NULL ) override;
 
-    long long GetLibraryTimestamp() const override
+    long long GetLibraryTimestamp( const wxString& aLibraryPath ) const override
     {
-        return getModificationTime( m_lib_path ).GetValue().GetValue();
+        return getModificationTime( aLibraryPath ).GetValue().GetValue();
     }
 
     bool IsFootprintLibWritable( const wxString& aLibraryPath ) override

pcbnew/footprint_info_impl.cpp

@@ -118,7 +118,8 @@ void FOOTPRINT_LIST_IMPL::loader_job()
 bool FOOTPRINT_LIST_IMPL::ReadFootprintFiles( FP_LIB_TABLE* aTable, const wxString* aNickname,
                                               WX_PROGRESS_REPORTER* aProgressReporter )
 {
-    if( aTable->GenerateTimestamp( aNickname ) == m_list_timestamp )
+    long long libraryTimestamp = aTable->GenerateTimestamp( aNickname );
+    if( m_list_timestamp == libraryTimestamp )
         return true;
 
     m_progress_reporter = aProgressReporter;
@@ -166,7 +167,7 @@ bool FOOTPRINT_LIST_IMPL::ReadFootprintFiles( FP_LIB_TABLE* aTable, const wxStri
                     ( _( "Loading incomplete; cancelled by user." ), nullptr, nullptr, 0 ) );
     }
 
-    m_list_timestamp = aTable->GenerateTimestamp( aNickname );
+    m_list_timestamp = libraryTimestamp;
     m_progress_reporter = nullptr;
 
     return m_errors.empty();

pcbnew/github/github_plugin.cpp

@@ -464,6 +464,29 @@ void GITHUB_PLUGIN::cacheLib( const wxString& aLibraryPath, const PROPERTIES* aP
 }
 
 
+long long GITHUB_PLUGIN::GetLibraryTimestamp( const wxString& aLibraryPath ) const
+{
+    // This plugin currently relies on the nginx server for caching (see comments
+    // at top of file).
+    // Since only the nginx server holds the timestamp information, we must defeat
+    // all caching above the nginx server.
+    return wxDateTime::Now().GetValue().GetValue();
+
+#if 0
+    // If we have no cache, return a number which won't match any stored timestamps
+    if( !m_gh_cache || m_lib_path != aLibraryPath )
+        return wxDateTime::Now().GetValue().GetValue();
+
+    long long hash = m_gh_cache->GetTimestamp();
+
+    if( m_pretty_dir.size() )
+        hash += PCB_IO::GetLibraryTimestamp( m_pretty_dir );
+
+    return hash;
+#endif
+}
+
+
 bool GITHUB_PLUGIN::repoURL_zipURL( const wxString& aRepoURL, std::string* aZipURL )
 {
     // e.g. "https://github.com/liftoff-sr/pretty_footprints"

pcbnew/github/github_plugin.h

@@ -184,6 +184,8 @@ public:
 
     bool IsFootprintLibWritable( const wxString& aLibraryPath ) override;
 
+    long long GetLibraryTimestamp( const wxString& aLibraryPath ) const override;
+
     void FootprintLibOptions( PROPERTIES* aListToAppendTo ) const override;
 
     // Since I derive from PCB_IO, I have to implement this, else I'd inherit his, which is bad since

pcbnew/gpcb_plugin.cpp

@@ -1120,10 +1120,10 @@ bool GPCB_PLUGIN::FootprintLibDelete( const wxString& aLibraryPath, const PROPER
 }
 
 
-long long GPCB_PLUGIN::GetLibraryTimestamp() const
+long long GPCB_PLUGIN::GetLibraryTimestamp( const wxString& aLibraryPath ) const
 {
     // If we have no cache, return a number which won't match any stored timestamps
-    if( !m_cache )
+    if( !m_cache || !m_cache->IsPath( aLibraryPath ) )
         return wxDateTime::Now().GetValue().GetValue();
 
     return m_cache->GetTimestamp();

pcbnew/gpcb_plugin.h

@@ -77,7 +77,7 @@ public:
     bool FootprintLibDelete( const wxString& aLibraryPath,
                              const PROPERTIES* aProperties = NULL ) override;
 
-    long long GetLibraryTimestamp() const override;
+    long long GetLibraryTimestamp( const wxString& aLibraryPath ) const override;
 
     bool IsFootprintLibWritable( const wxString& aLibraryPath ) override;
 

pcbnew/io_mgr.h

@@ -358,7 +358,7 @@ public:
      * directory).
      * Timestamps should not be considered ordered; they either match or they don't.
      */
-    virtual long long GetLibraryTimestamp() const = 0;
+    virtual long long GetLibraryTimestamp( const wxString& aLibraryPath ) const = 0;
 
     /**
      * Function PrefetchLib

pcbnew/kicad_plugin.cpp

@@ -1947,7 +1947,7 @@ void PCB_IO::init( const PROPERTIES* aProperties )
 
 void PCB_IO::validateCache( const wxString& aLibraryPath, bool checkModified )
 {
-    if( !m_cache || ( checkModified && m_cache->IsModified() ) )
+    if( !m_cache || !m_cache->IsPath( aLibraryPath ) || ( checkModified && m_cache->IsModified() ) )
     {
         // a spectacular episode in memory management:
         delete m_cache;
@@ -2130,10 +2130,10 @@ void PCB_IO::FootprintDelete( const wxString& aLibraryPath, const wxString& aFoo
 
 
 
-long long PCB_IO::GetLibraryTimestamp() const
+long long PCB_IO::GetLibraryTimestamp( const wxString& aLibraryPath ) const
 {
     // If we have no cache, return a number which won't match any stored timestamps
-    if( !m_cache )
+    if( !m_cache || !m_cache->IsPath( aLibraryPath ) )
         return wxDateTime::Now().GetValue().GetValue();
 
     return m_cache->GetTimestamp();

pcbnew/kicad_plugin.h

@@ -133,7 +133,7 @@ public:
     void FootprintDelete( const wxString& aLibraryPath, const wxString& aFootprintName,
                           const PROPERTIES* aProperties = NULL ) override;
 
-    long long GetLibraryTimestamp() const override;
+    long long GetLibraryTimestamp( const wxString& aLibraryPath ) const override;
 
     void FootprintLibCreate( const wxString& aLibraryPath, const PROPERTIES* aProperties = NULL) override;
 

pcbnew/legacy_plugin.cpp

@@ -3383,10 +3383,10 @@ void LP_CACHE::LoadModules( LINE_READER* aReader )
 }
 
 
-long long LEGACY_PLUGIN::GetLibraryTimestamp() const
+long long LEGACY_PLUGIN::GetLibraryTimestamp( const wxString& aLibraryPath ) const
 {
     // If we have no cache, return a number which won't match any stored timestamps
-    if( !m_cache )
+    if( !m_cache || m_cache->m_lib_path != aLibraryPath )
         return wxDateTime::Now().GetValue().GetValue();
 
     return m_cache->GetLibModificationTime().GetValue().GetValue();

pcbnew/legacy_plugin.h

@@ -93,7 +93,7 @@ public:
     bool FootprintLibDelete( const wxString& aLibraryPath,
                              const PROPERTIES* aProperties = NULL ) override;
 
-    long long GetLibraryTimestamp() const override;
+    long long GetLibraryTimestamp( const wxString& aLibraryPath ) const override;
 
     bool IsFootprintLibWritable( const wxString& aLibraryPath ) override;
 

pcbnew/pcad2kicadpcb_plugin/pcad_plugin.h

@@ -47,7 +47,7 @@ public:
 
     const wxString  GetFileExtension() const override;
 
-    long long GetLibraryTimestamp() const override
+    long long GetLibraryTimestamp( const wxString& aLibraryPath ) const override
     {
         // No support for libraries....
         return 0;