private boolean generateChecksums()

in src/main/org/apache/tools/ant/taskdefs/Checksum.java [470:574]
93 lines of code
16 McCabe index (conditional complexity)

    private boolean generateChecksums() throws BuildException {
        boolean checksumMatches = true;
        InputStream fis = null;
        OutputStream fos = null;
        byte[] buf = new byte[readBufferSize];
        try {
            for (Map.Entry<File, Object> e : includeFileMap.entrySet()) {
                messageDigest.reset();
                File src = e.getKey();
                if (!isCondition) {
                    log("Calculating " + algorithm + " checksum for " + src, Project.MSG_VERBOSE);
                }
                fis = Files.newInputStream(src.toPath());
                DigestInputStream dis = new DigestInputStream(fis,
                                                              messageDigest);
                while (dis.read(buf, 0, readBufferSize) != -1) {
                    // Empty statement
                }
                dis.close();
                fis.close();
                fis = null;
                byte[] fileDigest = messageDigest.digest();
                if (totalproperty != null) {
                    allDigests.put(src, fileDigest);
                }
                String checksum = createDigestString(fileDigest);
                //can either be a property name string or a file
                Object destination = e.getValue();
                if (destination instanceof String) {
                    String prop = (String) destination;
                    if (isCondition) {
                        checksumMatches
                            = checksumMatches && checksum.equals(property);
                    } else {
                        getProject().setNewProperty(prop, checksum);
                    }
                } else if (destination instanceof File) {
                    if (isCondition) {
                        File existingFile = (File) destination;
                        if (existingFile.exists()) {
                            try {
                                String suppliedChecksum =
                                    readChecksum(existingFile);
                                checksumMatches = checksumMatches
                                    && checksum.equals(suppliedChecksum);
                            } catch (BuildException be) {
                                // file is on wrong format, swallow
                                checksumMatches = false;
                            }
                        } else {
                            checksumMatches = false;
                        }
                    } else {
                        File dest = (File) destination;
                        fos = Files.newOutputStream(dest.toPath());
                        fos.write(format.format(new Object[] {
                                                    checksum,
                                                    src.getName(),
                                                    FileUtils
                                                    .getRelativePath(dest
                                                                     .getParentFile(),
                                                                     src),
                                                    FileUtils
                                                    .getRelativePath(getProject()
                                                                     .getBaseDir(),
                                                                     src),
                                                    src.getAbsolutePath()
                                                }).getBytes());
                        fos.write(System.lineSeparator().getBytes());
                        fos.close();
                        fos = null;
                    }
                }
            }
            if (totalproperty != null) {
                // Calculate the total checksum
                // Convert the keys (source files) into a sorted array.
                File[] keyArray = allDigests.keySet().toArray(new File[0]);
                // File is Comparable, but sort-order is platform
                // dependent (case-insensitive on Windows)
                Arrays.sort(keyArray, Comparator.nullsFirst(
                    Comparator.comparing(this::getRelativeFilePath)));

                // Loop over the checksums and generate a total hash.
                messageDigest.reset();
                for (File src : keyArray) {
                    // Add the digest for the file content
                    byte[] digest = allDigests.get(src);
                    messageDigest.update(digest);

                    // Add the file path
                    String fileName = getRelativeFilePath(src);
                    messageDigest.update(fileName.getBytes());
                }
                String totalChecksum = createDigestString(messageDigest.digest());
                getProject().setNewProperty(totalproperty, totalChecksum);
            }
        } catch (Exception e) {
            throw new BuildException(e, getLocation());
        } finally {
            FileUtils.close(fis);
            FileUtils.close(fos);
        }
        return checksumMatches;
    }