Implement OTA updates of translations

Check for and download updated translations periodically.

Over-the-Air updates like this decouple translations from Poedit code
releases and allow both faster updates and proof-reading / testing of
translations directly in the app.

deps/boost/Boost.xcodeproj/project.pbxproj

@@ -15,6 +15,7 @@
 		B2167C331815ADF0003A1428 /* portability.cpp in Sources */ = {isa = PBXBuildFile; fileRef = B2167C2C1815ADF0003A1428 /* portability.cpp */; };
 		B2167C341815ADF0003A1428 /* unique_path.cpp in Sources */ = {isa = PBXBuildFile; fileRef = B2167C2D1815ADF0003A1428 /* unique_path.cpp */; };
 		B2167C351815ADF0003A1428 /* utf8_codecvt_facet.cpp in Sources */ = {isa = PBXBuildFile; fileRef = B2167C2E1815ADF0003A1428 /* utf8_codecvt_facet.cpp */; };
+		B24D1D092AE95B3A00FB31D9 /* gzip.cpp in Sources */ = {isa = PBXBuildFile; fileRef = B24D1D082AE95B3A00FB31D9 /* gzip.cpp */; };
 		B287410C1815AF6000C4051F /* future.cpp in Sources */ = {isa = PBXBuildFile; fileRef = B28741061815AF6000C4051F /* future.cpp */; };
 		B287410D1815AF6000C4051F /* once.cpp in Sources */ = {isa = PBXBuildFile; fileRef = B28741081815AF6000C4051F /* once.cpp */; };
 		B287410F1815AF6000C4051F /* thread.cpp in Sources */ = {isa = PBXBuildFile; fileRef = B287410A1815AF6000C4051F /* thread.cpp */; };
@@ -53,6 +54,7 @@
 		B2167C2E1815ADF0003A1428 /* utf8_codecvt_facet.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; name = utf8_codecvt_facet.cpp; path = libs/filesystem/src/utf8_codecvt_facet.cpp; sourceTree = "<group>"; };
 		B2167C3B1815AEA5003A1428 /* libboost_thread.a */ = {isa = PBXFileReference; explicitFileType = archive.ar; includeInIndex = 0; path = libboost_thread.a; sourceTree = BUILT_PRODUCTS_DIR; };
 		B228A1561AD95CB9006B0BBC /* third_party.xcconfig */ = {isa = PBXFileReference; lastKnownFileType = text.xcconfig; name = third_party.xcconfig; path = ../custom_build/third_party.xcconfig; sourceTree = "<group>"; };
+		B24D1D082AE95B3A00FB31D9 /* gzip.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; name = gzip.cpp; path = libs/iostreams/src/gzip.cpp; sourceTree = "<group>"; };
 		B28741061815AF6000C4051F /* future.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; name = future.cpp; path = libs/thread/src/future.cpp; sourceTree = "<group>"; };
 		B28741081815AF6000C4051F /* once.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = once.cpp; sourceTree = "<group>"; };
 		B287410A1815AF6000C4051F /* thread.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = thread.cpp; sourceTree = "<group>"; };
@@ -230,6 +232,7 @@
 				B287414D1815B0FB00C4051F /* file_descriptor.cpp */,
 				B287414E1815B0FB00C4051F /* mapped_file.cpp */,
 				B287414F1815B0FB00C4051F /* zlib.cpp */,
+				B24D1D082AE95B3A00FB31D9 /* gzip.cpp */,
 			);
 			name = boost_iostreams;
 			sourceTree = "<group>";
@@ -497,6 +500,7 @@
 				B28741511815B0FB00C4051F /* mapped_file.cpp in Sources */,
 				B28741501815B0FB00C4051F /* file_descriptor.cpp in Sources */,
 				B28741521815B0FB00C4051F /* zlib.cpp in Sources */,
+				B24D1D092AE95B3A00FB31D9 /* gzip.cpp in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};

src/configuration.cpp

@@ -259,6 +259,18 @@ void Config::Write(const std::string& key, bool value)
     wxConfig::Get()->Write(key, value);
 }
 
+bool Config::Read(const std::string& key, long *out)
+{
+    CfgLock lock;
+    return wxConfig::Get()->Read(key, out);
+}
+
+void Config::Write(const std::string& key, long value)
+{
+    CfgLock lock;
+    wxConfig::Get()->Write(key, value);
+}
+
 
 ::PretranslateSettings Config::PretranslateSettings()
 {

src/configuration.h

@@ -73,6 +73,12 @@ class Config
     static std::string LocalazyMetadata() { return Read("/accounts/localazy/metadata", std::string()); }
     static void LocalazyMetadata(const std::string& prj) { return Write("/accounts/localazy/metadata", prj); }
 
+    static time_t OTATranslationLastCheck() { return Read("/ota/last_check", (long)0); }
+    static void OTATranslationLastCheck(time_t when) { Write("/ota/last_check", (long)when); }
+
+    static std::string OTATranslationEtag() { return Read("/ota/etag", std::string()); }
+    static void OTATranslationEtag(const std::string& etag) { Write("/ota/etag", etag); }
+
 private:
     template<typename T>
     static T Read(const std::string& key, T defval)
@@ -87,10 +93,12 @@ class Config
     static bool Read(const std::string& key, std::string *out);
     static bool Read(const std::string& key, std::wstring *out);
     static bool Read(const std::string& key, bool *out);
+    static bool Read(const std::string& key, long *out);
 
     static void Write(const std::string& key, const std::string& value);
     static void Write(const std::string& key, const std::wstring& value);
     static void Write(const std::string& key, bool value);
+    static void Write(const std::string& key, long value);
 };
 
 #endif // Poedit_configuration_h

src/edapp.cpp

@@ -47,6 +47,12 @@
 #include <wx/ipc.h>
 #include <wx/translation.h>
 
+#include <iostream>
+#include <fstream>
+#include <boost/iostreams/copy.hpp>
+#include <boost/iostreams/filtering_stream.hpp>
+#include <boost/iostreams/filter/gzip.hpp>
+
 #ifdef __WXOSX__
 #include "macos_helpers.h"
 #endif
@@ -584,7 +590,7 @@ void PoeditApp::SetupLanguage()
         if (langinfo)
         {
             language = langinfo->Language;
-            uilang.clear(); // will go through locale
+            // keep 'uilang' for use below 
         }
     }
 #endif
@@ -623,8 +629,69 @@ void PoeditApp::SetupLanguage()
 #ifdef __WXMSW__
     win_sparkle_set_lang(bestTrans.utf8_str());
 #endif
+
+#ifdef SUPPORTS_OTA_UPDATES
+    SetupOTALanguageUpdate(trans, str::to_utf8(bestTrans));
+#endif
 }
 
+#ifdef SUPPORTS_OTA_UPDATES
+void PoeditApp::SetupOTALanguageUpdate(wxTranslations *trans, const std::string& lang)
+{
+    if (lang == "en")
+        return;
+
+    // use downloaded OTA translations:
+    auto dir = GetCacheDir("Translations") + "/" + POEDIT_VERSION;
+    wxFileTranslationsLoader::AddCatalogLookupPathPrefix(dir);
+    trans->AddCatalog("poedit-ota");
+
+    // ..and update them (but at most once a day):
+    auto lastCheck = Config::OTATranslationLastCheck();
+    auto now = time(NULL);
+    if (now < lastCheck + 24*60*60)
+        return;
+    Config::OTATranslationLastCheck(now);
+
+    wxFileName mofile(dir + "/" + lang + "/poedit-ota.mo");
+    wxFileName::Mkdir(mofile.GetPath(), wxS_DIR_DEFAULT, wxPATH_MKDIR_FULL);
+
+    http_client::headers hdrs;
+    std::string etag;
+    if (mofile.FileExists())
+        etag = Config::OTATranslationEtag();
+    if (!etag.empty())
+        hdrs.emplace_back("If-None-Match", etag);
+
+    http_client::download_from_anywhere("https://ota.poedit.net/i18n/" POEDIT_VERSION "/" + lang + "/poedit-ota.mo.gz", hdrs)
+    .then_on_main([=](downloaded_file f)
+    {
+        TempOutputFileFor temp(mofile);
+        std::ofstream output_file(temp.FileName().fn_str(), std::ios_base::binary);
+        std::ifstream input_file(f.filename().GetFullPath().mb_str(), std::ios_base::binary);
+
+        if (output_file.fail() || input_file.fail())
+            return;
+
+        boost::iostreams::filtering_istream input;
+        input.push(boost::iostreams::gzip_decompressor());
+        input.push(input_file);
+
+        boost::iostreams::copy(input, output_file);
+        input_file.close();
+        output_file.close();
+
+        temp.Commit();
+        Config::OTATranslationEtag(f.etag());
+
+        // re-add the catalog to force reloading updated file
+        trans->AddCatalog("poedit-ota");
+    })
+    .catch_all([](dispatch::exception_ptr){});
+}
+#endif // SUPPORTS_OTA_UPDATES
+
+
 wxLayoutDirection PoeditApp::GetLayoutDirection() const
 {
     return g_layoutDirection;

src/edapp.h

@@ -39,6 +39,9 @@
 class WXDLLIMPEXP_FWD_BASE wxConfigBase;
 class WXDLLIMPEXP_FWD_BASE wxSingleInstanceChecker;
 
+#if defined(HAVE_HTTP_CLIENT) && (defined(__WXMSW__) || defined(__WXOSX__))
+    #define SUPPORTS_OTA_UPDATES
+#endif
 
 /// wxApp for use with
 class PoeditApp : public wxApp, public MenusManager
@@ -104,6 +107,9 @@ class PoeditApp : public wxApp, public MenusManager
         void HandleCustomURI(const wxString& uri);
 
         void SetupLanguage();
+#ifdef SUPPORTS_OTA_UPDATES
+        void SetupOTALanguageUpdate(wxTranslations *trans, const std::string& lang);
+#endif
 
         // App-global menu commands:
         void OnNewFromScratch(wxCommandEvent& event);

src/utility.h

@@ -253,6 +253,8 @@ class TempOutputFileFor
 {
 public:
     explicit TempOutputFileFor(const wxString& filename);
+    explicit TempOutputFileFor(const wxFileName& filename) : TempOutputFileFor(filename.GetFullPath()) {}
+
     ~TempOutputFileFor();
 
     /// Name of the temporary placeholder