private void insertFile()

in freemarker-docgen-core/src/main/java/org/freemarker/docgen/core/PrintTextWithDocgenSubstitutionsDirective.java [253:301]
46 lines of code
12 McCabe index (conditional complexity)

        private void insertFile(InsertDirectiveArgs args) throws TemplateException, IOException {
            int slashIndex = args.path.indexOf("/");
            String symbolicNameStep = slashIndex != -1 ? args.path.substring(0, slashIndex) : args.path;
            if (!symbolicNameStep.startsWith("@") || symbolicNameStep.length() < 2) {
                throw newErrorInDocgenTag("Path argument must start with @<symbolicName>/, "
                        + " where <symbolicName> is in " + transform.getInsertableFiles().keySet() + ".");
            }
            String symbolicName = symbolicNameStep.substring(1);
            Path symbolicNamePath = transform.getInsertableFiles().get(symbolicName);
            if (symbolicNamePath == null) {
                throw newErrorInDocgenTag("Symbolic insertable file name "
                        + StringUtil.jQuote(symbolicName) + " is not amongst the defined names: "
                        + transform.getInsertableFiles().keySet());
            }
            symbolicNamePath = symbolicNamePath.toAbsolutePath().normalize();
            Path resolvedFilePath = slashIndex != -1
                    ? symbolicNamePath.resolve(args.path.substring(slashIndex + 1))
                    : symbolicNamePath;
            resolvedFilePath = resolvedFilePath.normalize();
            if (!resolvedFilePath.startsWith(symbolicNamePath)) {
                throw newErrorInDocgenTag("Resolved path ("
                        + resolvedFilePath + ") is not inside the base path ("
                        + symbolicNamePath + ").");
            }
            if (!Files.isRegularFile(resolvedFilePath)) {
                throw newErrorInDocgenTag("Not an existing file: " + resolvedFilePath);
            }

            Charset charset;
            if (args.charset != null) {
                try {
                    charset = Charset.forName(args.charset);
                } catch (UnsupportedCharsetException e) {
                    throw newErrorInDocgenTag("Unsupported charset: " + args.charset);
                }
            } else {
                charset = StandardCharsets.UTF_8;
            }

            try (InputStream in = Files.newInputStream(resolvedFilePath)) {
                String fileContent = IOUtils.toString(in, charset);
                String fileExt = FilenameUtils.getExtension(resolvedFilePath.getFileName().toString());
                if (fileExt != null && fileExt.toLowerCase().startsWith("ftl")) {
                    fileContent = removeFTLCopyrightComment(fileContent);
                }

                cutAndInsertContent(args, fileContent);
            }
        }