feat: improve error reporting during import/merge

* check relevant file permissions before running opossum-file
* assume that all errors happening during opossum-file execution can be interpreted as the input file being invalid

Author: PhilippMa

src/ElectronBackend/main/listeners.ts

@@ -209,6 +209,12 @@ export function getImportFileConvertAndLoadListener(
         throw new Error('Input file does not exist');
       }
 
+      try {
+        fs.accessSync(resourceFilePath, fs.constants.R_OK);
+      } catch (error) {
+        throw new Error('Permission error: cannot read input file');
+      }
+
       if (!opossumFilePath.trim()) {
         throw new Error('No .opossum save location selected');
       }
@@ -221,6 +227,12 @@ export function getImportFileConvertAndLoadListener(
         throw new Error('Output directory does not exist');
       }
 
+      try {
+        fs.accessSync(path.dirname(opossumFilePath), fs.constants.W_OK);
+      } catch (error) {
+        throw new Error('Permission error: cannot write to output directory');
+      }
+
       logger.info('Converting input file to .opossum format');
       await convertToOpossum(resourceFilePath, opossumFilePath, fileType);
 
@@ -254,6 +266,12 @@ export function getMergeFileAndLoadListener(
         throw new Error('Input file does not exist');
       }
 
+      try {
+        fs.accessSync(inputFilePath, fs.constants.R_OK);
+      } catch (error) {
+        throw new Error('Permission error: cannot read input file');
+      }
+
       const currentlyOpenOpossumFilePath =
         getGlobalBackendState().opossumFilePath;
 

src/ElectronBackend/opossum-file/ExternalFileConverter.ts

@@ -22,9 +22,7 @@ export abstract class ExternalFileConverter extends FileConverter {
         toBeConvertedFilePath,
       ]);
     } catch (error) {
-      throw new Error(
-        `Conversion of ${this.fileTypeName} file to .opossum file failed`,
-      );
+      throw new Error(`Input file is not a valid ${this.fileTypeName} file`);
     }
   }
 }

src/ElectronBackend/opossum-file/FileConverter.ts

@@ -47,14 +47,12 @@ export abstract class FileConverter {
         '--opossum',
         opossumFilePath,
       ]);
-
-      if (preConvertedFilePath) {
-        fs.rmSync(preConvertedFilePath);
-      }
     } catch (error) {
-      throw new Error(
-        `Merging ${this.fileTypeName} file into current file failed`,
-      );
+      throw new Error(`Input file is not a valid ${this.fileTypeName} file`);
+    }
+
+    if (preConvertedFilePath) {
+      fs.rmSync(preConvertedFilePath);
     }
   }
 }

src/ElectronBackend/opossum-file/LegacyFileConverter.ts

@@ -67,24 +67,22 @@ export class LegacyFileConverter extends FileConverter {
     toBeConvertedFilePath: string,
     opossumSaveLocation: string,
   ): Promise<void> {
-    try {
-      let pathToInputJson = toBeConvertedFilePath;
+    let pathToInputJson = toBeConvertedFilePath;
 
-      if (toBeConvertedFilePath.endsWith(legacyOutputFileEnding)) {
-        pathToInputJson = this.tryToGetLegacyInputJsonFromLegacyOutputJson(
-          toBeConvertedFilePath,
-        );
-      }
+    if (toBeConvertedFilePath.endsWith(legacyOutputFileEnding)) {
+      pathToInputJson = this.tryToGetLegacyInputJsonFromLegacyOutputJson(
+        toBeConvertedFilePath,
+      );
+    }
 
+    try {
       await writeOpossumFile({
         path: opossumSaveLocation,
         input: this.readInputJson(pathToInputJson),
         output: this.readOutputJson(pathToInputJson),
       });
     } catch (error) {
-      throw new Error(
-        'Conversion of Legacy Opossum file to .opossum file failed',
-      );
+      throw new Error('Input file is not a valid Legacy Opossum file');
     }
   }
 

src/ElectronBackend/opossum-file/opossum-file.ts

@@ -15,7 +15,7 @@ const fileTypeToConverter: Record<FileType, FileConverter> = {
   })(),
   [FileType.OWASP_JSON]: new (class extends ExternalFileConverter {
     readonly fileTypeSwitch: string = '--owasp-json';
-    readonly fileTypeName: string = 'OWASP Dependency-check';
+    readonly fileTypeName: string = 'OWASP Dependency-Check';
   })(),
 };