Limited Support for Form Controls V2 (ListBox, Buttons, etc.) (#3130)

* WIP Limited Support for Form Controls V2 (ListBox, Buttons, etc.)

This is a replacement for draft PR #2455 and draft PR #3127. There is some useful commentary in those PRs which I have mostly, but not entirely, duplicated below. Fix #2396. Fix #1770. Fix #2388.

A related problem is that the vml files used for the form controls sometimes contain invalid xml. Fix #3125 (rejected previous PR #1181 as too risky, issue was also reported as #170). Vml file should be valid Xml, but Excel can generate unclosed `<br>` tags, preventing Xlsx reader from reading file correctly. I believe a very narrowly targeted fix, changing `<br>` to `<br/>`, and only when reading vml files, probably mitigates the risk. The sample file formscomments.xlsx which is part of this change shows this problem with `Button 1` on sheet `Forms`; the spreadsheet was created with Excel 365, so the problem is not restricted to Excel 2013 as originally reported. A comment on PR 3127 indicates that other tags might be involved, but, without a file demonstrating that, I will restrict this change to br tags for now.

I am starting this out in draft status, and will probably leave it that way for some time. I'm not sure where we want to go with this. It fixes some problems, but in a limited manner, and creates some others. I'm not sure the pain of the others is balanced considering the limitations of the fix. If enough interest is generated as a result of this ticket being out there, we can proceed; if not, it probably isn't worth it.

This fix allows form control elements to be read in and written out. It does not allow you to add such elements, nor even to locate them or determine their properties (so you can't modify or delete them). Although it handles reading and writing of sheets containing both form controls and comments, it will probably create a corrupt spreadsheet if you try adding a new comment to a sheet with form controls - probably quite difficult to solve. Cloning the sheet probably won't work either - probably easier than the other. It is conceivable that we want to add a new property to the Xlsx Reader which turns the reading of form elements on or off (default=off), so that negative effects will be limited to those who have explictly opted in. The change in its current form does not implement such a property.

Because of its limitations, the change isn't really testable. As in some other recent installs, I have added a sample to demonstrate that it works correctly.

As it turns out, if we have a worksheet which contains both form controls and comments (see formscomments.xlsx which is part of this PR), PhpSpreadsheet already creates a corrupt file when it tries to load and save the spreadsheet with such a worksheet. With this change, the file is saved without corruption. This tilts things in favor of proceeding. I'm still not ready, but this will be an important consideration.

A sample file for issue #2621 illustrated a problem with shape files. Since they are involved here, I took a look at how the sample worked with this code. In master, and with this change, a corrupt file results. Fixing that is probably easier than the general problem of handling shape files, but it's an argument against moving this forward until the corruption problem can be addressed.

Fix #2661. A template including checkboxes was leading to file corruption solved by this PR. Another argument for moving forward.

* Improved Sample File, and Documentation

Add more realistic worksheet to spreadsheet. Document new feature, adding caveats to how it can be used.

docs/topics/reading-and-writing-to-file.md

@@ -184,6 +184,22 @@ code:
 it disables several Office2007 file format options, resulting in a
 lower-featured Office2007 spreadsheet.
 
+### Form Control Fields
+
+PhpSpreadsheet offers limited support for Forms Controls (buttons,
+checkboxes, etc.). The support is available only for Excel 2007 format,
+and is offered solely to allow loading a spreadsheet with such controls
+and saving it as a new file.
+Support is not available for adding such elements to the spreadsheet,
+nor even to locate them to determine their properties
+(so you can't modify or delete them).
+Modifications to a worksheet with controls are "caveat emptor";
+some modifications will work correctly,
+but others are very likely to cause problems,
+e.g. adding a comment to the worksheet,
+or inserting or deleting rows or columns in a manner that would
+cause the controls to change location.
+
 ## Excel 5 (BIFF) file format
 
 Xls file format is the old Excel file format, implemented in

samples/Reader/22_Reader_formscomments.php

@@ -0,0 +1,22 @@
+<?php
+
+use PhpOffice\PhpSpreadsheet\IOFactory;
+
+require __DIR__ . '/../Header.php';
+
+$helper->log('Start');
+
+$inputFileType = 'Xlsx';
+$inputFileName = __DIR__ . '/sampleData/formscomments.xlsx';
+
+$helper->log('Loading file ' . $inputFileName . ' using IOFactory with a defined reader type of ' . $inputFileType);
+$reader = IOFactory::createReader($inputFileType);
+$helper->log('Loading all WorkSheets');
+$reader->setLoadAllSheets();
+$spreadsheet = $reader->load($inputFileName);
+
+// Save
+$helper->write($spreadsheet, __FILE__, ['Xlsx']);
+$spreadsheet->disconnectWorksheets();
+
+$helper->log('end');

samples/Reader/22_Reader_issue1767.php

@@ -17,5 +17,6 @@
 
 // Save
 $helper->write($spreadsheet, __FILE__);
+$spreadsheet->disconnectWorksheets();
 
 $helper->log('end');

src/PhpSpreadsheet/Reader/Xlsx.php

@@ -122,9 +122,12 @@ public static function falseToArray($value): array
         return is_array($value) ? $value : [];
     }
 
-    private function loadZip(string $filename, string $ns = ''): SimpleXMLElement
+    private function loadZip(string $filename, string $ns = '', bool $replaceUnclosedBr = false): SimpleXMLElement
     {
         $contents = $this->getFromZipArchive($this->zip, $filename);
+        if ($replaceUnclosedBr) {
+            $contents = str_replace('<br>', '<br/>', $contents);
+        }
         $rels = simplexml_load_string(
             $this->securityScanner->scan($contents),
             'SimpleXMLElement',
@@ -1029,6 +1032,7 @@ protected function loadSpreadsheetFromFile(string $filename): Spreadsheet
 
                                 // later we will remove from it real vmlComments
                                 $unparsedVmlDrawings = $vmlComments;
+                                $vmlDrawingContents = [];
 
                                 // Loop through VML comments
                                 foreach ($vmlComments as $relName => $relPath) {
@@ -1037,7 +1041,7 @@ protected function loadSpreadsheetFromFile(string $filename): Spreadsheet
 
                                     try {
                                         // no namespace okay - processed with Xpath
-                                        $vmlCommentsFile = $this->loadZip($relPath, '');
+                                        $vmlCommentsFile = $this->loadZip($relPath, '', true);
                                         $vmlCommentsFile->registerXPathNamespace('v', Namespaces::URN_VML);
                                     } catch (Throwable $ex) {
                                         //Ignore unparsable vmlDrawings. Later they will be moved from $unparsedVmlDrawings to $unparsedLoadedData
@@ -1047,6 +1051,7 @@ protected function loadSpreadsheetFromFile(string $filename): Spreadsheet
                                     // Locate VML drawings image relations
                                     $drowingImages = [];
                                     $VMLDrawingsRelations = dirname($relPath) . '/_rels/' . basename($relPath) . '.rels';
+                                    $vmlDrawingContents[$relName] = $this->securityScanner->scan($this->getFromZipArchive($zip, $relPath));
                                     if ($zip->locateName($VMLDrawingsRelations)) {
                                         $relsVMLDrawing = $this->loadZip($VMLDrawingsRelations, Namespaces::RELATIONSHIPS);
                                         foreach ($relsVMLDrawing->Relationship as $elex) {
@@ -1519,6 +1524,14 @@ protected function loadSpreadsheetFromFile(string $filename): Spreadsheet
                                             }
                                         }
                                     }
+                                    if ($xmlSheet->legacyDrawing && !$this->readDataOnly) {
+                                        foreach ($xmlSheet->legacyDrawing as $drawing) {
+                                            $drawingRelId = (string) self::getArrayItem(self::getAttributes($drawing, $xmlNamespaceBase), 'id');
+                                            if (isset($vmlDrawingContents[$drawingRelId])) {
+                                                $unparsedLoadedData['sheets'][$docSheet->getCodeName()]['legacyDrawing'] = $vmlDrawingContents[$drawingRelId];
+                                            }
+                                        }
+                                    }
 
                                     // unparsed drawing AlternateContent
                                     $xmlAltDrawing = $this->loadZip((string) $fileDrawing, Namespaces::COMPATIBILITY);

src/PhpSpreadsheet/Writer/Xlsx.php

@@ -455,14 +455,17 @@ public function save($filename, int $flags = 0): void
             }
 
             // Add comment relationship parts
-            if (count($this->spreadSheet->getSheet($i)->getComments()) > 0) {
+            $legacy = $unparsedLoadedData['sheets'][$this->spreadSheet->getSheet($i)->getCodeName()]['legacyDrawing'] ?? null;
+            if (count($this->spreadSheet->getSheet($i)->getComments()) > 0 || $legacy !== null) {
                 // VML Comments relationships
                 $zipContent['xl/drawings/_rels/vmlDrawing' . ($i + 1) . '.vml.rels'] = $this->getWriterPartRels()->writeVMLDrawingRelationships($this->spreadSheet->getSheet($i));
 
                 // VML Comments
-                $zipContent['xl/drawings/vmlDrawing' . ($i + 1) . '.vml'] = $this->getWriterPartComments()->writeVMLComments($this->spreadSheet->getSheet($i));
+                $zipContent['xl/drawings/vmlDrawing' . ($i + 1) . '.vml'] = $legacy ?? $this->getWriterPartComments()->writeVMLComments($this->spreadSheet->getSheet($i));
+            }
 
-                // Comments
+            // Comments
+            if (count($this->spreadSheet->getSheet($i)->getComments()) > 0) {
                 $zipContent['xl/comments' . ($i + 1) . '.xml'] = $this->getWriterPartComments()->writeComments($this->spreadSheet->getSheet($i));
 
                 // Media
@@ -477,7 +480,9 @@ public function save($filename, int $flags = 0): void
             // Add unparsed relationship parts
             if (isset($unparsedLoadedData['sheets'][$sheetCodeName]['vmlDrawings'])) {
                 foreach ($unparsedLoadedData['sheets'][$sheetCodeName]['vmlDrawings'] as $vmlDrawing) {
-                    $zipContent[$vmlDrawing['filePath']] = $vmlDrawing['content'];
+                    if (!isset($zipContent[$vmlDrawing['filePath']])) {
+                        $zipContent[$vmlDrawing['filePath']] = $vmlDrawing['content'];
+                    }
                 }
             }
 

src/PhpSpreadsheet/Writer/Xlsx/Rels.php

@@ -239,14 +239,16 @@ public function writeWorksheetRelationships(\PhpOffice\PhpSpreadsheet\Worksheet\
 
         // Write comments relationship?
         $i = 1;
-        if (count($worksheet->getComments()) > 0) {
+        if (count($worksheet->getComments()) > 0 || isset($unparsedLoadedData['sheets'][$worksheet->getCodeName()]['legacyDrawing'])) {
             $this->writeRelationship(
                 $objWriter,
                 '_comments_vml' . $i,
                 Namespaces::VML,
                 '../drawings/vmlDrawing' . $worksheetId . '.vml'
             );
+        }
 
+        if (count($worksheet->getComments()) > 0) {
             $this->writeRelationship(
                 $objWriter,
                 '_comments' . $i,

src/PhpSpreadsheet/Writer/Xlsx/Worksheet.php

@@ -1333,7 +1333,8 @@ private function writeDrawings(XMLWriter $objWriter, PhpspreadsheetWorksheet $wo
     private function writeLegacyDrawing(XMLWriter $objWriter, PhpspreadsheetWorksheet $worksheet): void
     {
         // If sheet contains comments, add the relationships
-        if (count($worksheet->getComments()) > 0) {
+        $unparsedLoadedData = $worksheet->getParent()->getUnparsedLoadedData();
+        if (count($worksheet->getComments()) > 0 || isset($unparsedLoadedData['sheets'][$worksheet->getCodeName()]['legacyDrawing'])) {
             $objWriter->startElement('legacyDrawing');
             $objWriter->writeAttribute('r:id', 'rId_comments_vml1');
             $objWriter->endElement();