kicad/pcbnew/github/github_plugin.h

/*
 * This program source code file is part of KiCad, a free EDA CAD application.
 *
 * Copyright (C) 2013 SoftPLC Corporation, Dick Hollenbeck <dick@softplc.com>
 * Copyright (C) 2016-2017 KiCad Developers, see AUTHORS.txt for contributors.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, you may find one here:
 * http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
 * or you may search the http://www.gnu.org website for the version 2 license,
 * or you may write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
 */

#ifndef GITHUB_PLUGIN_H_
#define GITHUB_PLUGIN_H_

#include <kicad_plugin.h>

struct GH_CACHE;


/**
   Class GITHUB_PLUGIN
   implements a portion of pcbnew's PLUGIN interface to provide read only access
   to a github repo consisting of pretty footprints, and optionally provides "Copy On Write"
   support of edited footprints.

   <p>It could have used version 3 of the github.com API documented here:

   <pre>
       http://developer.github.com/v3/
       https://help.github.com/articles/creating-an-access-token-for-command-line-use
   </pre>

   but it does not, since a better technique was discovered. Cleverly this
   plugin simply reads in a zip file of the repo and unzips it from RAM as
   needed. Therefore this "Github" plugin is <b>read only for accessing remote
   pretty libraries at https://github.com.</b>

   <p>The fp-lib-table dialog is entered via menu choice "Preferences | Library
   Tables". For easy options editing in the current row, click on the "Edit
   Options" button. The "Library Path" in the fp-lib-table row for a Github
   library should be set to the full https:// URL.

   <p>For example:

   <pre>
        https://github.com/liftoff-sr/pretty_footprints
   </pre>

   This is typically

   <pre>
        https://github.com/user_name/repo_name
   </pre>
   <p>

   The "Plugin Type" should be set to "Github".

   <p>This plugin also supports "Copy On Write", a.k.a. "COW". Thus a Github
   library may take an optional option called
   <b>allow_pretty_writing_to_this_dir</b>. This option is essentially the
   "Library Path" for a local "KiCad" (pretty) type library which is combined to
   make up the Github library found in the same fp-lib-table row. If the option
   is missing, then the Github library is read only as always. If the option is
   present for a Github library, then any writes to this hybrid library will go
   to the local *.pretty directory. Note that the github.com resident portion of
   this hybrid COW library is always read only, meaning you cannot delete
   anything or modify any footprint at github directly. The aggregate library
   type remains "Github" in your discussions, but it consists of a local R/W
   portion and a remote R/O portion.

   <p>Below is an fp-lib-table entry for the case without option
   <b>allow_pretty_writing_to_this_dir</b>:

    <table>
        <tr>
        <th>Nickname</th><th>Library Path</th><th>Plugin Type</th><th>Options</th><th>Description</th>
        </tr>

        <tr>
        <td>github</td><td>https://github.com/liftoff-sr/pretty_footprints</td><td>Github</td>
            <td></td><td>Liftoff's GH footprints</td>
        </tr>
   </table>

   Below is an fp-lib-table entry with the COW option given. Note the use of the environment variable
   ${HOME}, as an example only.  The github.pretty directory is based in ${HOME}/pretty/.  Anytime you
   use option allow_pretty_writing_to_this_dir, you will create that directory manually and it must
   end in extension <b>.pretty</b>.

    <table>
        <tr>
        <th>Nickname</th><th>Library Path</th><th>Plugin Type</th><th>Options</th><th>Description</th>
        </tr>

        <tr>

        <td>github</td><td>https://github.com/liftoff-sr/pretty_footprints</td><td>Github</td>
            <td>allow_pretty_writing_to_this_dir=${HOME}/pretty/github.pretty</td>
            <td>Liftoff's GH footprints</td>
        </tr>
   </table>

   <p>Any footprint loads will always give precedence to the local footprints
   found in the pretty dir given by option
   <b>allow_pretty_writing_to_this_dir</b>. So once you have written to the COW
   library's local directory by doing a footprint save, no github updates will
   be seen when loading a footprint by the same name as one for which you've
   written locally.

   <p>Always keep a separate local *.pretty directory for each Github library,
   never combine them by referring to the same directory more than once. Also,
   do not also use the same COW (*.pretty) directory in a "KiCad" fp-lib-table
   entry. This would likely create a mess. The COW directory should be manually
   created in advance, and the directory name must end with ".pretty". The value
   of the option <b>allow_pretty_writing_to_this_dir</b> will be path
   substituted with any environment variable strings embedded, just like the
   "Library Path" is.

   <p>What's the point of COW? It is to turbo-charge the sharing of footprints.
   If you periodically email your COW pretty footprint modifications to the
   Github repo maintainer, you can help update the Github copy. Simply email the
   individual *.kicad_mod files you find in your COW directories. After you've
   received confirmation that your changes have been committed up at github.com,
   you can safely delete your COW file(s) and those from github.com will flow
   down. Your goal should be to keep the COW file set as small as possible by
   contributing frequently to the shared master copies at https://github.com.

   <p>Note that if you use the module editor to delete a footprint and it is
   present in the COW local dir, it will get deleted from there. However, it may
   not be deleted from the library as a whole if the footprint of the same name
   also exists in the github repo. In this case deleting the local copy will
   simply unmask the one at the github repo. Remember, it is masked out if there
   is a local COW copy, since the local copy always takes precedence. And
   remember you cannot modify the github copy except by emailing a COW
   modification to the repo maintainer.

   <p>If you happen to be the repo maintainer, then the obvious solution for you
   is to make your COW directory <b>be</b> your working copy directory. From
   there you can push to github. And you can receive *.kicad_mod files by email
   and put them into your local working copy directory also and do diffs,
   reverting or denying when appropriate, editing when appropriate before
   pushing or denying the change. Ultimately you would owe the sender either a
   note of acceptance or denial by email.

   @author Dick Hollenbeck
   @date Original date: 10-Sep-2013

 */
class GITHUB_PLUGIN : public PCB_IO
{
public:
    //-----<PLUGIN API>----------------------------------------------------------
    const wxString PluginName() const override;

    const wxString GetFileExtension() const override;

    void FootprintEnumerate( wxArrayString& aFootprintNames, const wxString& aLibraryPath,
            const PROPERTIES* aProperties = NULL ) override;

    void PrefetchLib( const wxString& aLibraryPath,
            const PROPERTIES* aProperties = NULL ) override;

    MODULE* FootprintLoad( const wxString& aLibraryPath,
            const wxString& aFootprintName, const PROPERTIES* aProperties ) override;

    void FootprintSave( const wxString& aLibraryPath, const MODULE* aFootprint,
            const PROPERTIES* aProperties = NULL ) override;

    void FootprintDelete( const wxString& aLibraryPath, const wxString& aFootprintName,
            const PROPERTIES* aProperties = NULL ) override;

    bool IsFootprintLibWritable( const wxString& aLibraryPath ) 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
    // my lib_path is not his.  Note: it is impossible to create a Github library, but can the C.O.W. portion.
    void FootprintLibCreate( const wxString& aLibraryPath, const PROPERTIES* aProperties ) override;

    // Since I derive from PCB_IO, I have to implement this, else I'd inherit his, which is bad since
    // my lib_path is not his.  Note: it is impossible to delete a Github library, but can the C.O.W portion.
    bool FootprintLibDelete( const wxString& aLibraryPath, const PROPERTIES* aProperties ) override;

    //-----</PLUGIN API>---------------------------------------------------------

    GITHUB_PLUGIN();        // constructor, if any, must be zero arg
    ~GITHUB_PLUGIN();

protected:

    void init( const PROPERTIES* aProperties );

    void cacheLib( const wxString& aLibraryPath, const PROPERTIES* aProperties );

    /**
     * Function repoURL_zipURL
     * translates a repo URL to a zipfile URL name as commonly seen on github.com
     *
     * @param  aRepoURL points to the base of the repo.
     * @param  aZipURL is where to put the zip file URL.
     * @return bool - true if @a aRepoULR was parseable, else false
     */
    static bool repoURL_zipURL( const wxString& aRepoURL, std::string* aZipURL );

    /**
     * Function remoteGetZip
     * fetches a zip file image from a github repo synchronously.  The byte image
     * is received into the m_input_stream. If the image has already been stored,
     * do nothing.
     */
    void remoteGetZip( const wxString& aRepoURL ) throw( IO_ERROR );

    wxString    m_lib_path;     ///< from aLibraryPath, something like https://github.com/liftoff-sr/pretty_footprints
    std::string m_zip_image;    ///< byte image of the zip file in its entirety.
    GH_CACHE*   m_gh_cache;
    wxString    m_pretty_dir;
};


#endif // GITHUB_PLUGIN_H_