Fix types and precompute blob sizes to avoid overflows

src/components/views/messages/MImageBody.tsx

@@ -179,7 +179,7 @@ export default class MImageBody extends React.Component<IProps, IState> {
     };
 
     protected getContentUrl(): string {
-        const content = this.props.mxEvent.getContent();
+        const content: IMediaEventContent= this.props.mxEvent.getContent();
         if (this.props.forExport) return content.url || content.file.url;
         const media = mediaFromContent(content);
         if (media.isEncrypted) {

src/utils/exportUtils/HtmlExport.tsx

@@ -306,13 +306,17 @@ export default class HTMLExporter extends Exporter {
             if (this.exportOptions.attachmentsIncluded) {
                 try {
                     const blob = await this.getMediaBlob(mxEv);
+                    if (this.totalSize + blob.size > this.exportOptions.maxSize) {
+                        eventTile = await this.getEventTile(this.createModifiedEvent(this.mediaOmitText, mxEv), joined);
+                    } else {
                         this.totalSize += blob.size;
                         const filePath = this.getFilePath(mxEv);
                         eventTile = await this.getEventTile(mxEv, joined, filePath);
-                    if (this.totalSize > this.exportOptions.maxSize - 1024 * 512) {
+                        if (this.totalSize == this.exportOptions.maxSize) {
                             this.exportOptions.attachmentsIncluded = false;
                         }
                         this.addFile(filePath, blob);
+                    }
                 } catch (e) {
                     console.log("Error while fetching file" + e);
                     eventTile = await this.getEventTile(
@@ -339,7 +343,7 @@ export default class HTMLExporter extends Exporter {
 
             content += this._wantsDateSeparator(event, prevEvent) ? this.getDateSeparator(event) : "";
             const shouldBeJoined = !this._wantsDateSeparator(event, prevEvent)
-                                       && shouldFormContinuation(prevEvent, event);
+                                       && shouldFormContinuation(prevEvent, event, false);
             const body = await this.createMessageBody(event, shouldBeJoined);
             this.totalSize += Buffer.byteLength(body);
             content += body;

src/utils/exportUtils/JSONExport.ts

@@ -45,12 +45,14 @@ export default class JSONExporter extends Exporter {
         if (this.exportOptions.attachmentsIncluded && this.isAttachment(mxEv)) {
             try {
                 const blob = await this.getMediaBlob(mxEv);
+                if (this.totalSize + blob.size < this.exportOptions.maxSize) {
                     this.totalSize += blob.size;
                     const filePath = this.getFilePath(mxEv);
-                this.addFile(filePath, blob);
+                    if (this.totalSize == this.exportOptions.maxSize) {
-                if (this.totalSize > this.exportOptions.maxSize - 1024 * 1024) {
                         this.exportOptions.attachmentsIncluded = false;
                     }
+                    this.addFile(filePath, blob);
+                }
             } catch (err) {
                 console.log("Error fetching file: " + err);
             }

src/utils/exportUtils/PlainTextExport.ts

@@ -66,13 +66,17 @@ export default class PlainTextExporter extends Exporter {
             if (this.exportOptions.attachmentsIncluded) {
                 try {
                     const blob = await this.getMediaBlob(mxEv);
+                    if (this.totalSize + blob.size > this.exportOptions.maxSize) {
+                        mediaText = ` (${this.mediaOmitText})`;
+                    } else {
                         this.totalSize += blob.size;
                         const filePath = this.getFilePath(mxEv);
                         mediaText = " (" + _t("File Attached") + ")";
                         this.addFile(filePath, blob);
-                    if (this.totalSize > this.exportOptions.maxSize - 1024 * 1024) {
+                        if (this.totalSize == this.exportOptions.maxSize) {
                             this.exportOptions.attachmentsIncluded = false;
                         }
+                    }
                 } catch (error) {
                     mediaText = " (" + _t("Error fetching file") + ")";
                     console.log("Error fetching file " + error);

src/utils/exportUtils/ZipStream.ts

@@ -223,8 +223,8 @@ export default function streamToZIP(underlyingSource: UnderlyingSource) {
     function closeZip() {
         let length = 0;
         let index = 0;
-        let indexFilename;
+        let indexFilename: number;
-        let file;
+        let file: any;
 
         for (indexFilename = 0; indexFilename < filenames.length; indexFilename++) {
             file = files[filenames[indexFilename]];