Add improved iOS logging

This addition adds more insight into iOS crashes, especially for failures in JS that result in the crash.
Using this logging we were able to identify this issue: NativeScript/NativeScript#5475 which otherwise would have been impossible to trace, as it had a 5% repro among users but never occurred internally.

Author: Dick Smith

publish/scripts/installer.js

@@ -292,28 +292,109 @@ function writeBuildscriptHook(enable) {
     console.log("Install Crashlytics buildscript hook.");
     try {
         var scriptContent =
-`var fs = require('fs-extra');
-var path = require('path');
-var xcode = require('xcode');
+`const fs = require('fs-extra');
+const path = require('path');
+const xcode = require('xcode');
+
+const pattern1 = /\\n\\s*\\/\\/Crashlytics 1 BEGIN[\\s\\w]*\\/\\/Crashlytics 1 END.*\\n/m;
+const pattern2 = /\\n\\s*\\/\\/Crashlytics 2 BEGIN[\\s\\w]*\\/\\/Crashlytics 2 END.*\\n/m;
+const pattern3 = /\\n\\s*\\/\\/Crashlytics 3 BEGIN[\\s\\w]*\\/\\/Crashlytics 3 END.*\\n/m;
+
+const string1 = \`
+//Crashlytics 1 BEGIN
+#else
+#import <Crashlytics/CLSLogging.h>
+#endif
+//Crashlytics 1 END
+\`;
+
+const string2 = \`
+#if DEBUG
+#else
+//Crashlytics 2 BEGIN
+static int redirect_cls(const char *prefix, const char *buffer, int size) {
+  CLSLog(@"%s: %.*s", prefix, size, buffer);
+  return size;
+}
+
+static int stderr_redirect(void *inFD, const char *buffer, int size) {
+  return redirect_cls("stderr", buffer, size);
+}
 
+static int stdout_redirect(void *inFD, const char *buffer, int size) {
+  return redirect_cls("stdout", buffer, size);
+}
+//Crashlytics 2 END
+#endif
+\`;
+
+const string3 = \`
+//Crashlytics 3 BEGIN
+#if DEBUG
+#else
+  // Per https://docs.fabric.io/apple/crashlytics/enhanced-reports.html#custom-logs :
+  // Crashlytics ensures that all log entries are recorded, even if the very next line of code crashes.
+  // This means that logging must incur some IO. Be careful when logging in performance-critical areas.
+  
+  // As per the note above, enabling this can affect performance if too much logging is present.
+  // stdout->_write = stdout_redirect;
+  
+  // stderr usually only occurs during critical failures;
+  // so it is usually essential to identifying crashes, especially in JS
+  stderr->_write = stderr_redirect;
+//Crashlytics 3 END
+#endif
+\`;
 
 module.exports = function($logger, $projectData, hookArgs) {
-  var platform = hookArgs.platform.toLowerCase();
+  const platform = hookArgs.platform.toLowerCase();
   return new Promise(function(resolve, reject) {
-    var isNativeProjectPrepared = !hookArgs.nativePrepare || !hookArgs.nativePrepare.skipNativePrepare;
+    const isNativeProjectPrepared = !hookArgs.nativePrepare || !hookArgs.nativePrepare.skipNativePrepare;
     if (isNativeProjectPrepared) {
       try {
         if (platform === 'ios') {
-          var appName = path.basename($projectData.projectDir);
-          var sanitizedName = appName.split('').filter(function(c) { return /[a-zA-Z0-9]/.test(c); }).join('');
-          var projectPath = path.join($projectData.platformsDir, 'ios', sanitizedName + '.xcodeproj', 'project.pbxproj');
-          $logger.trace('Using Xcode project', projectPath);
-          var xcodeProject = xcode.project(projectPath);
-          xcodeProject.parseSync();
-          var options = { shellPath: '/bin/sh', shellScript: '\${PODS_ROOT}/Fabric/run' };
-          var buildPhase = xcodeProject.addBuildPhase([], 'PBXShellScriptBuildPhase', 'Configure Crashlytics', xcodeProject.getFirstTarget().uuid, options).buildPhase;
-          fs.writeFileSync(projectPath, xcodeProject.writeSync());
-          $logger.trace('Xcode project written');
+          const sanitizedAppName = path.basename($projectData.projectDir).split('').filter((c) => /[a-zA-Z0-9]/.test(c)).join('');
+
+          // write buildscript for dSYM upload
+          const xcodeProjectPath = path.join($projectData.platformsDir, 'ios', sanitizedAppName + '.xcodeproj', 'project.pbxproj');
+          $logger.trace('Using Xcode project', xcodeProjectPath);
+          if (fs.existsSync(xcodeProjectPath)) {
+            var xcodeProject = xcode.project(xcodeProjectPath);
+            xcodeProject.parseSync();
+            var options = { shellPath: '/bin/sh', shellScript: '\${PODS_ROOT}/Fabric/run' };
+            xcodeProject.addBuildPhase(
+              [], 'PBXShellScriptBuildPhase', 'Configure Crashlytics', xcodeProject.getFirstTarget().uuid, options
+            ).buildPhase;
+            fs.writeFileSync(xcodeProjectPath, xcodeProject.writeSync());
+            $logger.trace('Xcode project written');
+          } else {
+            $logger.error(xcodeProjectPath + ' is missing.');
+            reject()
+          }
+
+          // Logging from stdout/stderr
+          $logger.out('Add iOS crash logging');
+          const mainmPath = path.join($projectData.platformsDir, 'ios', 'internal', 'main.m');
+          if (fs.existsSync(mainmPath)) {
+            let mainmContent = fs.readFileSync(mainmPath).toString();
+            // string1
+            mainmContent = pattern1.test(mainmPath)
+              ? mainmContent.replace(pattern1, string1)
+              : mainmContent.replace(/(\\n#endif\\n)/, string1);
+            // string2
+            mainmContent = pattern2.test(mainmPath)
+              ? mainmContent.replace(pattern2, string2)
+              : mainmContent.replace(/(\\nint main.*)/, string2 + '$1');
+            // string3
+            mainmContent = pattern3.test(mainmPath)
+              ? mainmContent.replace(pattern3, string3)
+              : mainmContent.replace(/(int main.*\\n)/, '$1' + string3 + '\\n');
+            fs.writeFileSync(mainmPath, mainmContent);
+          } else {
+            $logger.error(mainmPath + ' is missing.');
+            reject()
+          }
+
           resolve();
         } else {
           resolve();
@@ -515,7 +596,7 @@ module.exports = function($logger, $projectData) {
     });
 };
 `;
-        console.log("Writing 'firebase-build-gradle.js' to " + appRoot + "/hooks/after-prepare");
+        console.log("Writing 'firebase-build-gradle.js' to " + appRoot + "hooks/after-prepare");
         var scriptPath = path.join(appRoot, "hooks", "after-prepare", "firebase-build-gradle.js");
         fs.writeFileSync(scriptPath, scriptContent);
     } catch(e) {