From e7fdad875a568a93d8f7438c875d42d77748462b Mon Sep 17 00:00:00 2001
From: Alberto Griggio <agriggio@users.noreply.github.com>
Date: Mon, 9 Dec 2019 04:27:13 -0800
Subject: [PATCH] metadata: cache recent files for faster operation

(cherry picked from commit 6ee014ddb7ab77537289e1f41f13345e5db54710)
---
 rtengine/metadata.cc      | 22 ++++++++++++++++++----
 rtengine/metadata.h       | 10 +++++-----
 rtgui/procparamchangers.h | 15 ++++++++-------
 3 files changed, 31 insertions(+), 16 deletions(-)

diff --git a/rtengine/metadata.cc b/rtengine/metadata.cc
index bfcb3080e..70e8b785a 100644
--- a/rtengine/metadata.cc
+++ b/rtengine/metadata.cc
@@ -21,6 +21,7 @@
 #include <stdio.h>
 #include <glib/gstdio.h>
 #include <iostream>
+#include <giomm.h>
 
 #include "metadata.h"
 #include "settings.h"
@@ -32,9 +33,12 @@ namespace rtengine {
 
 extern const Settings *settings;
 
+std::unique_ptr<Exiv2Metadata::ImageCache> Exiv2Metadata::cache_(nullptr);
 
 namespace {
 
+constexpr size_t IMAGE_CACHE_SIZE = 200;
+
 Exiv2::Image::AutoPtr open_exiv2(const Glib::ustring& fname)
 {
 #ifdef EXV_UNICODE_PATH
@@ -88,10 +92,19 @@ Exiv2Metadata::Exiv2Metadata(const Glib::ustring &path, bool merge_xmp_sidecar):
 
 void Exiv2Metadata::load() const
 {
-    if (!src_.empty() && !image_.get()) {
-        auto img = open_exiv2(src_);
-        image_.reset(img.release());
-        image_->readMetadata();
+    if (!src_.empty() && !image_.get() && Glib::file_test(src_.c_str(), Glib::FILE_TEST_EXISTS)) {
+        CacheVal val;
+        auto finfo = Gio::File::create_for_path(src_)->query_info(G_FILE_ATTRIBUTE_TIME_MODIFIED);
+        if (cache_ && cache_->get(src_, val) && val.second >= finfo->modification_time()) {
+            image_ = val.first;
+        } else {
+            auto img = open_exiv2(src_);
+            image_.reset(img.release());
+            image_->readMetadata();
+            if (cache_) {
+                cache_->set(src_, CacheVal(image_, finfo->modification_time()));
+            }
+        }
 
         if (merge_xmp_) {
             do_merge_xmp(image_.get());
@@ -319,6 +332,7 @@ Exiv2::XmpData Exiv2Metadata::getXmpSidecar(const Glib::ustring &path)
 
 void Exiv2Metadata::init()
 {
+    cache_.reset(new ImageCache(IMAGE_CACHE_SIZE));
     Exiv2::XmpParser::initialize();
 }
 
diff --git a/rtengine/metadata.h b/rtengine/metadata.h
index 5f19fa5a1..57904d4a4 100644
--- a/rtengine/metadata.h
+++ b/rtengine/metadata.h
@@ -24,6 +24,7 @@
 #include <exiv2/exiv2.hpp>
 #include <memory>
 #include "procparams.h"
+#include "cache.h"
 
 namespace rtengine {
 
@@ -74,11 +75,10 @@ private:
     Exiv2::ExifData exif_data_;
     Exiv2::IptcData iptc_data_;
     Exiv2::XmpData xmp_data_;
+
+    typedef std::pair<std::shared_ptr<Exiv2::Image>, Glib::TimeVal> CacheVal;
+    typedef Cache<Glib::ustring, CacheVal> ImageCache;
+    static std::unique_ptr<ImageCache> cache_;
 };
 
-// Glib::ustring get_xmp_sidecar_path(const Glib::ustring &path);
-// Exiv2::Image::AutoPtr open_exiv2(const Glib::ustring &fname,
-//                                  bool merge_xmp_sidecar);
-// Exiv2::XmpData read_exiv2_xmp(const Glib::ustring &fname);
-
 } // namespace rtengine
diff --git a/rtgui/procparamchangers.h b/rtgui/procparamchangers.h
index 8dd3769c6..0ca76a0eb 100644
--- a/rtgui/procparamchangers.h
+++ b/rtgui/procparamchangers.h
@@ -1,4 +1,5 @@
-/*
+/* -*- C++ -*-
+ *  
  *  This file is part of RawTherapee.
  *
  *  Copyright (c) 2004-2010 Gabor Horvath <hgabor@rawtherapee.com>
@@ -16,9 +17,9 @@
  *  You should have received a copy of the GNU General Public License
  *  along with RawTherapee.  If not, see <https://www.gnu.org/licenses/>.
  */
-#define UNKNOWN    -1
-#define FILEBROWSER 1
-#define EDITOR      2
-#define BATCHEDITOR 3
-#define CACHEMGR    4
-#define SAFETYUPDATE 5
+constexpr int UNKNOWN = -1;
+constexpr int FILEBROWSER = 1;
+constexpr int EDITOR = 2;
+constexpr int BATCHEDITOR = 3;
+constexpr int CACHEMGR = 4;
+constexpr int SAFETYUPDATE = 5;