From ec6c703c60ead5f362606d76badb782c157db0d8 Mon Sep 17 00:00:00 2001
From: Yousif Yassi <yousif@heartex.com>
Date: Fri, 1 Dec 2023 12:21:33 -0500
Subject: [PATCH] fix: DIA-743: [FE] Blank space is displayed instead of the
 records on scroll up/down

---
 src/components/CellViews/ImageCell.js     | 13 +++-
 src/components/DataManager/DataManager.js | 27 ++++----
 src/components/Label/Label.js             | 77 ++++++++++-----------
 src/providers/ImageProvider.js            | 81 +++++++++++++++++++++++
 4 files changed, 148 insertions(+), 50 deletions(-)
 create mode 100644 src/providers/ImageProvider.js

diff --git a/src/components/CellViews/ImageCell.js b/src/components/CellViews/ImageCell.js
index 1c9b498d..2f8db7dc 100644
--- a/src/components/CellViews/ImageCell.js
+++ b/src/components/CellViews/ImageCell.js
@@ -1,6 +1,8 @@
 import { getRoot } from "mobx-state-tree";
 import { FF_LSDV_4711, isFF } from "../../utils/feature-flags";
 import { AnnotationPreview } from "../Common/AnnotationPreview/AnnotationPreview";
+import { useRef } from "react";
+import { useImageProvider } from "../../providers/ImageProvider";
 
 const imgDefaultProps = {};
 
@@ -13,23 +15,32 @@ export const ImageCell = (column) => {
     column: { alias },
   } = column;
   const root = getRoot(original);
+  const imgRef = useRef();
+  const { getImage } = useImageProvider();
 
   const renderImagePreview = original.total_annotations === 0 || !root.showPreviews;
   const imgSrc = Array.isArray(value) ? value[0] : value;
 
   if (!imgSrc) return null;
+  getImage(imgSrc).then((loadedImage) => {
+    if (imgRef.current && loadedImage.loaded && loadedImage.url) {
+      imgRef.current.setAttribute("src", loadedImage.url);
+      imgRef.current.style.display = "";
+    }
+  });
 
   return renderImagePreview ? (
     <img
       {...imgDefaultProps}
+      ref={imgRef}
       key={imgSrc}
-      src={imgSrc}
       alt="Data"
       style={{
         maxHeight: "100%",
         maxWidth: "100px",
         objectFit: "contain",
         borderRadius: 3,
+        display: "none",
       }}
     />
   ) : (
diff --git a/src/components/DataManager/DataManager.js b/src/components/DataManager/DataManager.js
index 71899ab3..90911bc5 100644
--- a/src/components/DataManager/DataManager.js
+++ b/src/components/DataManager/DataManager.js
@@ -11,6 +11,7 @@ import { FiltersSidebar } from "../Filters/FiltersSidebar/FilterSidebar";
 import { DataView } from "../MainView";
 import "./DataManager.styl";
 import { Toolbar } from "./Toolbar/Toolbar";
+import { ImageProvider } from "../../providers/ImageProvider";
 
 const injector = inject(({ store }) => {
   const { sidebarEnabled, sidebarVisible } = store.viewsStore ?? {};
@@ -127,19 +128,21 @@ const TabsSwitch = switchInjector(observer(({ sdk, views, tabs, selectedKey }) =
 
 export const DataManager = injector(({ shrinkWidth }) => {
   return (
-    <Block name="tabs-content">
-      <Elem name="tab" mod={{ shrink: shrinkWidth }}>
-        <Interface name="tabs">
-          <TabsSwitch />
-        </Interface>
+    <ImageProvider key="app-image-provider">
+      <Block name="tabs-content">
+        <Elem name="tab" mod={{ shrink: shrinkWidth }}>
+          <Interface name="tabs">
+            <TabsSwitch />
+          </Interface>
 
-        <Interface name="toolbar">
-          <Toolbar />
-        </Interface>
+          <Interface name="toolbar">
+            <Toolbar />
+          </Interface>
 
-        <DataView />
-      </Elem>
-      <FiltersSidebar />
-    </Block>
+          <DataView />
+        </Elem>
+        <FiltersSidebar />
+      </Block>
+    </ImageProvider>
   );
 });
diff --git a/src/components/Label/Label.js b/src/components/Label/Label.js
index 942769f5..aeca3ceb 100644
--- a/src/components/Label/Label.js
+++ b/src/components/Label/Label.js
@@ -11,6 +11,7 @@ import { Resizer } from "../Common/Resizer/Resizer";
 import { Space } from "../Common/Space/Space";
 import { DataView } from "../MainView";
 import "./Label.styl";
+import { ImageProvider } from "../../providers/ImageProvider";
 
 const LabelingHeader = ({ SDK, onClick, isExplorerMode }) => {
   return (
@@ -99,45 +100,47 @@ export const Labeling = injector(observer(({
   const outlinerEnabled = isFF(FF_DEV_1170);
 
   return (
-    <Block name="label-view" mod={{ loading }}>
-      {SDK.interfaceEnabled("labelingHeader") && (
-        <LabelingHeader
-          SDK={SDK}
-          onClick={closeLabeling}
-          isExplorerMode={isExplorerMode}
-        />
-      )}
-
-      <Elem name="content">
-        {isExplorerMode && (
-          <Elem name="table">
-            <Elem
-              tag={Resizer}
-              name="dataview"
-              minWidth={200}
-              showResizerLine={false}
-              type={'quickview'}
-              maxWidth={window.innerWidth * 0.35}
-              initialWidth={view.labelingTableWidth} // hardcoded as in main-menu-trigger
-              onResizeFinished={onResize}
-              style={{ display: "flex", flex: 1, width: '100%' }}
-            >
-              <DataView />
-            </Elem>
-          </Elem>
+    <ImageProvider key="app-image-provider">
+      <Block name="label-view" mod={{ loading }}>
+        {SDK.interfaceEnabled("labelingHeader") && (
+          <LabelingHeader
+            SDK={SDK}
+            onClick={closeLabeling}
+            isExplorerMode={isExplorerMode}
+          />
         )}
 
-        <Elem name="lsf-wrapper" mod={{ mode: isExplorerMode ? "explorer" : "labeling" }}>
-          {loading && <Elem name="waiting" mod={{ animated: true }}/>}
-          <Elem
-            ref={lsfRef}
-            id="label-studio-dm"
-            name="lsf-container"
-            key="label-studio"
-            mod={{ outliner: outlinerEnabled }}
-          />
+        <Elem name="content">
+          {isExplorerMode && (
+            <Elem name="table">
+              <Elem
+                tag={Resizer}
+                name="dataview"
+                minWidth={200}
+                showResizerLine={false}
+                type={'quickview'}
+                maxWidth={window.innerWidth * 0.35}
+                initialWidth={view.labelingTableWidth} // hardcoded as in main-menu-trigger
+                onResizeFinished={onResize}
+                style={{ display: "flex", flex: 1, width: '100%' }}
+              >
+                <DataView />
+              </Elem>
+            </Elem>
+          )}
+
+          <Elem name="lsf-wrapper" mod={{ mode: isExplorerMode ? "explorer" : "labeling" }}>
+            {loading && <Elem name="waiting" mod={{ animated: true }}/>}
+            <Elem
+              ref={lsfRef}
+              id="label-studio-dm"
+              name="lsf-container"
+              key="label-studio"
+              mod={{ outliner: outlinerEnabled }}
+            />
+          </Elem>
         </Elem>
-      </Elem>
-    </Block>
+      </Block>
+    </ImageProvider>
   );
 }));
diff --git a/src/providers/ImageProvider.js b/src/providers/ImageProvider.js
new file mode 100644
index 00000000..d345faa1
--- /dev/null
+++ b/src/providers/ImageProvider.js
@@ -0,0 +1,81 @@
+import React, { useCallback, useContext, useMemo, useRef } from "react";
+
+export const ImageContext = React.createContext({});
+ImageContext.displayName = "ImageContext";
+
+export const ImageProvider = ({ children }) => {
+  const loadedImagesRef = useRef(new Map());
+  const getImage = useCallback((imgSrc) => {
+    const loadedImages = loadedImagesRef.current;
+
+    if (loadedImages.has(imgSrc)) {
+      const loadedImage = loadedImages.get(imgSrc);
+      
+      return loadedImage.promise;
+    }
+    const imageFetchPromise = fetch(imgSrc)
+      .then((response) => {
+        const reader = response.body.getReader();
+  
+        return new ReadableStream({
+          start(controller) {
+            return pump();
+            function pump() {
+              return reader.read().then(({ done, value }) => {
+                // When no more data needs to be consumed, close the stream
+                if (done) {
+                  controller.close();
+                  return;
+                }
+                // Enqueue the next data chunk into our target stream
+                controller.enqueue(value);
+                return pump();
+              });
+            }
+          },
+        });
+      })
+      // Create a new response out of the stream
+      .then((stream) => new Response(stream))
+      // Create an object URL for the response
+      .then((response) => response.blob())
+      .then((blob) => URL.createObjectURL(blob))
+      // Update image
+      .then((url) => {
+        loadedImages.set(imgSrc, {
+          url,
+          promise: imageFetchPromise,
+          loaded: true,
+        });
+        return loadedImages.get(imgSrc);
+      })
+      .catch((err) => {
+        console.error(err);
+        return loadedImages.get(imgSrc);
+      }); 
+      
+    loadedImages.set(imgSrc, {
+      url: imgSrc,
+      promise: imageFetchPromise,
+      loaded: false,
+    });
+
+    return imageFetchPromise;
+  }, []);
+  const contextValue = useMemo(() => {
+    return {
+      loadedImages: loadedImagesRef.current,
+      getImage,
+    };
+  }, [getImage]);
+
+  return (
+    <ImageContext.Provider value={contextValue}>
+      {children}
+    </ImageContext.Provider>
+  );
+};
+
+export const useImageProvider = () => {
+  return useContext(ImageContext) ?? {};
+};
\ No newline at end of file