/**
* checkProgram invokes the Haskell compiler on a given file and reports the output.
*
* @param pathToProgramFile Specifies the file or folder containing that should be compiled.
* (accepts .lhs and .hs files)
* @param compilerName The compiler to be used (usually ghc).
* @param compilerFlags Additional flags to be passed to the compiler.
* @throws FileNotFoundException Is thrown when the file in pathToProgramFile cannot be opened
* @throws BadCompilerSpecifiedException Is thrown when the given compiler cannot be called
* @return A {@link CompilerOutput} that contains all compiler messages and flags on how the
* compile run went.
* @throws BadFlagException When ghc doesn't recognize a flag, this exception is thrown.
*/
@Override
public CompilerOutput checkProgram(
Path pathToProgramFile, String compilerName, List<String> compilerFlags)
throws FileNotFoundException, BadCompilerSpecifiedException, BadFlagException {
Process compilerProcess = null;
try {
// create compiler invocation.
List<String> compilerInvocation =
createCompilerInvocation(pathToProgramFile, compilerName, compilerFlags);
ProcessBuilder compilerProcessBuilder = new ProcessBuilder(compilerInvocation);
// make sure the compiler stays in its directory.
compilerProcessBuilder.directory(pathToProgramFile.getParent().toFile());
compilerProcess = compilerProcessBuilder.start();
// this will never happen because createCompilerInvocation never
// throws this Exception. Throw declaration needs to be in method
// declaration because of the implemented Interface although we
// never use it in the HaskellCompileChecker
} catch (CompilerOutputFolderExistsException e) {
LOGGER.severe(
"A problem while compiling, which never should happen, occured" + e.getMessage());
} catch (BadCompilerSpecifiedException e) {
throw new BadCompilerSpecifiedException(e.getMessage());
} catch (IOException e) {
// If we cannot call the compiler we return a CompilerOutput
// initialized with false, false, indicating
// that the compiler wasn't invoked properly and that there was no
// clean Compile.
CompilerOutput compilerInvokeError = new CompilerOutput();
compilerInvokeError.setClean(false);
compilerInvokeError.setCompilerInvoked(false);
return compilerInvokeError;
}
// Now we read compiler output. If everything is ok ghc reports
// nothing in the errorStream.
InputStream compilerOutputStream = compilerProcess.getErrorStream();
InputStreamReader compilerStreamReader = new InputStreamReader(compilerOutputStream);
BufferedReader compilerOutputBuffer = new BufferedReader(compilerStreamReader);
String line;
CompilerOutput compilerOutput = new CompilerOutput();
compilerOutput.setCompilerInvoked(true);
List<String> compilerOutputLines = new LinkedList<>();
try {
while ((line = compilerOutputBuffer.readLine()) != null) {
compilerOutputLines.add(line);
}
// Errors are separated via an empty line (""). But after the
// the last error the OutputBuffer has nothing more to write.
// In order to recognize the last error we insert an empty String
// at the end of the list.
// Only needs to be done when there are errors.
if (compilerOutputLines.size() != 0) {
line = "";
compilerOutputLines.add(line);
}
compilerOutputStream.close();
compilerStreamReader.close();
compilerOutputBuffer.close();
compilerProcess.destroy();
} catch (IOException e) {
// Reading might go wrong here if ghc should unexpectedly die
LOGGER.severe("Error while reading from compiler stream.");
compilerOutput.setClean(false);
compilerOutput.setCompileStreamBroken(true);
return compilerOutput;
}
// ghc -c generates a .o(object) and a .hi(haskell interface) file.
// But we don't need those files so they can be deleted.
// The generated files have the same name like our input file so we
// can just exchange the file endings in order to get the
// correct file paths for deletion
if (Files.isDirectory(pathToProgramFile, LinkOption.NOFOLLOW_LINKS)) {
// we use a file walker in order to find all files in the folder
// and its subfolders
RegexDirectoryWalker dirWalker = new RegexDirectoryWalker(".+\\.([Ll])?[Hh][Ss]");
try {
Files.walkFileTree(pathToProgramFile, dirWalker);
} catch (IOException e) {
LOGGER.severe(
"Could not walk submission "
+ pathToProgramFile.toString()
+ " while building copiler invocation: "
+ e.getMessage());
}
for (Path candidatePath : dirWalker.getFoundFiles()) {
File candidateFile = candidatePath.toFile();
if (!candidateFile.isDirectory()) {
String extension = FilenameUtils.getExtension(candidateFile.toString());
if (extension.matches("[Ll]?[Hh][Ss]")) {
File ghcGeneratedObject =
new File(FilenameUtils.removeExtension(candidateFile.toString()) + ".o");
File ghcGeneratedInterface =
new File(FilenameUtils.removeExtension(candidateFile.toString()) + ".hi");
ghcGeneratedObject.delete();
ghcGeneratedInterface.delete();
}
}
}
} else {
String extension = FilenameUtils.getExtension(pathToProgramFile.toString());
if (extension.matches("[Ll]?[Hh][Ss]")) {
File ghcGeneratedObject =
new File(FilenameUtils.removeExtension(pathToProgramFile.toString()) + ".o");
File ghcGeneratedInterface =
new File(FilenameUtils.removeExtension(pathToProgramFile.toString()) + ".hi");
ghcGeneratedObject.delete();
ghcGeneratedInterface.delete();
}
}
// if there are no errors there is no Output to handle
if (compilerOutputLines.size() != 0) {
compilerOutput = splitCompilerOutput(compilerOutputLines, compilerOutput);
} else {
compilerOutput.setClean(true);
}
return compilerOutput;
}
/**
* This Method generates the command required to start the compiler. It generates a list of
* strings that can be passed to a process builder.
*
* @param pathToProgramFile Where to look for the main file that will be compiled.
* @param compilerName Which compiler to call
* @param compilerFlags User supplied flags to be passed
* @return List of string with the command for the process builder.
* @throws BadCompilerSpecifiedException When no compiler is given.
* @throws FileNotFoundException When the file to be compiled does not exist
* @throws CompilerOutputFolderExistsException Due to slightly uncompatible
* CompileCheckerInterface this exception is in the declaration but it is never thrown.
* JavaCompileChecker uses this exception.
*/
private List<String> createCompilerInvocation(
Path pathToProgramFile, String compilerName, List<String> compilerFlags)
throws BadCompilerSpecifiedException, FileNotFoundException,
CompilerOutputFolderExistsException {
List<String> compilerInvocation = new LinkedList<>();
// We need a compiler name. Without it we cannot compile anything and
// abort.
if (("".equals(compilerName)) || (compilerName == null)) {
throw new BadCompilerSpecifiedException("No compiler specified.");
} else {
compilerInvocation.add(compilerName);
}
// If compiler flags are passed, append them after the compiler name.
// If we didn't get any we append nothing.
if ((compilerFlags != null) && (!(compilerFlags.isEmpty()))) {
compilerInvocation.addAll(compilerFlags);
}
// now we tell ghc to stop after compilation because we just want to
// see if there are syntax errors in the code
compilerInvocation.add("-c");
// Check for the existence of the program file we are trying to
// compile.
if ((pathToProgramFile == null) || (pathToProgramFile.compareTo(Paths.get("")) == 0)) {
throw new FileNotFoundException("No file to compile specified");
} else {
if (Files.isDirectory(pathToProgramFile, LinkOption.NOFOLLOW_LINKS)) {
// we are supposed to compile a folder. Hence we'll scan for
// lhs files and pass them to the compiler.
RegexDirectoryWalker dirWalker = new RegexDirectoryWalker(".+\\.([Ll])?[Hh][Ss]");
try {
Files.walkFileTree(pathToProgramFile, dirWalker);
} catch (IOException e) {
LOGGER.severe(
"Could not walk submission "
+ pathToProgramFile.toString()
+ " while building compiler invocation: "
+ e.getMessage());
}
for (Path matchedFile : dirWalker.getFoundFiles()) {
compilerInvocation.add(matchedFile.toFile().getAbsolutePath());
}
} else if (Files.exists(pathToProgramFile, LinkOption.NOFOLLOW_LINKS)) {
// if the file exists, just pass the file name, since the
// compiler will
// be confined to the directory the file is in a few lines
// down.
compilerInvocation.add(pathToProgramFile.toString());
} else {
throw new FileNotFoundException(
"Program file that should be compiled does not exist."
+ "Filename : \""
+ pathToProgramFile.toString()
+ "\"");
}
}
return compilerInvocation;
}