Improve zotero://open-pdf handling

- Support Adobe Acrobat on macOS, with page number support via System
  Events. Tested with Acrobat Reader, but hopefully functional with
  non-Reader versions as well
- Use full path to configured .app via AppleScript rather than a
  hard-coded name, in case there are multiple versions on the system
- Simplify code and improve logging

chrome/content/zotero/xpcom/openPDF.js

@@ -27,37 +27,30 @@ Zotero.OpenPDF = {
 	openToPage: async function (path, page) {
 		var handler = Zotero.Prefs.get("fileHandler.pdf");
 		var opened = false;
+		
+		if (handler) {
+			Zotero.debug(`Custom handler is ${handler}`);
+		}
+		
 		if (Zotero.isMac) {
-			if (handler.includes('Preview')) {
+			if (!this._openWithHandlerMac(handler, path, page)) {
-				this._openWithPreview(path, page);
-			}
-			else if (handler.includes('Skim')) {
-				this._openWithSkim(path, page);
-			}
-			else if (handler.includes('PDF Expert')) {
-				this._openWithPDFExpert(path, page);
-			}
-			else {
 				// Try to detect default app
 				handler = this._getPDFHandlerName();
-				Zotero.debug(`Handler is ${handler}`);
+				if (!this._openWithHandlerMac(handler, path, page)) {
-				if (handler && handler == 'Skim') {
+					// Fall back to Preview
-					this._openWithSkim(path, page);
-				}
-				else if (handler && handler == 'PDF Expert') {
-					this._openWithPDFExpert(path, page);
-				}
-				// Fall back to Preview
-				else {
 					this._openWithPreview(path, page);
 				}
 			}
 			opened = true;
 		}
 		else if (Zotero.isWin) {
-			handler = handler || this._getPDFHandlerWindows();
+			if (!handler) {
+				handler = this._getPDFHandlerWindows();
+				if (handler) {
+					Zotero.debug(`Default handler is ${handler}`);
+				}
+			}
 			if (handler) {
-				Zotero.debug("Handler is " + handler);
 				// Include flags to open the PDF on a given page in various apps
 				//
 				// Adobe Acrobat: http://partners.adobe.com/public/developer/en/acrobat/PDFOpenParameters.pdf
@@ -71,28 +64,27 @@ Zotero.OpenPDF = {
 			}
 		}
 		else if (Zotero.isLinux) {
-			if (handler.includes('evince') || handler.includes('okular')) {
+			if (!handler) {
+				handler = await this._getPDFHandlerLinux();
+				if (handler) {
+					Zotero.debug(`Resolved handler is ${handler}`);
+				}
+			}
+			if (handler && (handler.includes('evince') || handler.includes('okular'))) {
 				this._openWithEvinceOrOkular(handler, path, page);
 				opened = true;
 			}
+			// Fall back to okular and then evince if unknown handler
+			else if (await OS.File.exists('/usr/bin/okular')) {
+				this._openWithEvinceOrOkular('/usr/bin/okular', path, page);
+				opened = true;
+			}
+			else if (await OS.File.exists('/usr/bin/evince')) {
+				this._openWithEvinceOrOkular('/usr/bin/evince', path, page);
+				opened = true;
+			}
 			else {
-				let handler = await this._getPDFHandlerLinux();
+				Zotero.debug("No handler found");
-				if (handler.includes('evince') || handler.includes('okular')) {
-					this._openWithEvinceOrOkular(handler, path, page);
-					opened = true;
-				}
-				// Fall back to okular and then evince if unknown handler
-				else if (await OS.File.exists('/usr/bin/okular')) {
-					this._openWithEvinceOrOkular('/usr/bin/okular', path, page);
-					opened = true;
-				}
-				else if (await OS.File.exists('/usr/bin/evince')) {
-					this._openWithEvinceOrOkular('/usr/bin/evince', path, page);
-					opened = true;
-				}
-				else {
-					Zotero.debug("No handler found");
-				}
 			}
 		}
 		return opened;
@@ -140,8 +132,31 @@ Zotero.OpenPDF = {
 	//
 	// Mac
 	//
+	_openWithHandlerMac: function (handler, path, page) {
+		if (!handler) {
+			return false;
+		}
+		if (handler.includes('Preview')) {
+			this._openWithPreview(path, page);
+			return true;
+		}
+		if (handler.includes('Adobe Acrobat')) {
+			this._openWithAcrobat(handler, path, page);
+			return true;
+		}
+		if (handler.includes('Skim')) {
+			this._openWithSkim(handler, path, page);
+			return true;
+		}
+		if (handler.includes('PDF Expert')) {
+			this._openWithPDFExpert(handler, path, page);
+			return true;
+		}
+		return false;
+	},
+	
 	_openWithPreview: async function (filePath, page) {
-		await Zotero.Utilities.Internal.exec('/usr/bin/open', ['-a', 'Preview', filePath]);
+		await Zotero.Utilities.Internal.exec('/usr/bin/open', ['-a', "Preview", filePath]);
 		// Go to page using AppleScript
 		let args = [
 			'-e', 'tell app "Preview" to activate',
@@ -152,24 +167,36 @@ Zotero.OpenPDF = {
 		await Zotero.Utilities.Internal.exec('/usr/bin/osascript', args);
 	},
 	
-	_openWithSkim: async function (filePath, page) {
+	_openWithAcrobat: async function (appPath, filePath, page) {
+		await Zotero.Utilities.Internal.exec('/usr/bin/open', ['-a', appPath, filePath]);
+		// Go to page using AppleScript
+		let args = [
+			'-e', `tell app "${appPath}" to activate`,
+			'-e', 'tell app "System Events" to keystroke "n" using {command down, shift down}',
+			'-e', `tell app "System Events" to keystroke "${page}"`,
+			'-e', 'tell app "System Events" to keystroke return'
+		];
+		await Zotero.Utilities.Internal.exec('/usr/bin/osascript', args);
+	},
+	
+	_openWithSkim: async function (appPath, filePath, page) {
 		// Escape double-quotes in path
 		var quoteRE = /"/g;
 		filePath = filePath.replace(quoteRE, '\\"');
 		let filename = OS.Path.basename(filePath).replace(quoteRE, '\\"');
 		let args = [
-			'-e', 'tell app "Skim" to activate',
+			'-e', `tell app "${appPath}" to activate`,
-			'-e', `tell app "Skim" to open "${filePath}"`
+			'-e', `tell app "${appPath}" to open "${filePath}"`
 		];
-		args.push('-e', `tell document "${filename}" of application "Skim" to go to page ${page}`);
+		args.push('-e', `tell document "${filename}" of application "${appPath}" to go to page ${page}`);
 		await Zotero.Utilities.Internal.exec('/usr/bin/osascript', args);
 	},
 	
-	_openWithPDFExpert: async function (filePath, page) {
+	_openWithPDFExpert: async function (appPath, filePath, page) {
-		await Zotero.Utilities.Internal.exec('/usr/bin/open', ['-a', 'PDF Expert', filePath]);
+		await Zotero.Utilities.Internal.exec('/usr/bin/open', ['-a', handlers, filePath]);
 		// Go to page using AppleScript (same as Preview)
 		let args = [
-			'-e', 'tell app "PDF Expert" to activate',
+			'-e', `tell app "${appPath}" to activate`,
 			'-e', 'tell app "System Events" to keystroke "g" using {option down, command down}',
 			'-e', `tell app "System Events" to keystroke "${page}"`,
 			'-e', 'tell app "System Events" to keystroke return'