valepakh commented on code in PR #7372: URL: https://github.com/apache/ignite-3/pull/7372#discussion_r2685434335
########## modules/cli/src/main/java/org/apache/ignite/internal/cli/core/repl/terminal/PagerSupport.java: ########## @@ -0,0 +1,208 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one or more + * contributor license agreements. See the NOTICE file distributed with + * this work for additional information regarding copyright ownership. + * The ASF licenses this file to You under the Apache License, Version 2.0 + * (the "License"); you may not use this file except in compliance with + * the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +package org.apache.ignite.internal.cli.core.repl.terminal; + +import java.io.IOException; +import java.io.OutputStream; +import java.nio.charset.StandardCharsets; +import org.apache.ignite.internal.cli.config.CliConfigKeys; +import org.apache.ignite.internal.cli.config.ConfigManagerProvider; +import org.jline.terminal.Terminal; + +/** + * Handles pager support in CLI REPL mode. + * + * <p>Provides functionality to pipe large outputs through a pager (like `less` or `more`) + * when the output exceeds the terminal height. + */ +public class PagerSupport { + + /** Default pager command. Uses less with flags: -R (ANSI colors), -F (quit if fits), -X (no clear). */ + public static final String DEFAULT_PAGER = "less -RFX"; + + /** Default pager command for Windows. */ + public static final String DEFAULT_PAGER_WINDOWS = "more"; + + /** Number of lines to reserve for prompt and status. */ + private static final int TERMINAL_MARGIN = 2; + + private final int terminalHeight; + private final boolean pagerEnabled; + private final String pagerCommand; + private final Terminal terminal; + + /** + * Creates PagerSupport for production use. + * + * @param terminal JLine terminal instance + * @param configManagerProvider configuration manager provider + */ + public PagerSupport(Terminal terminal, ConfigManagerProvider configManagerProvider) { + this.terminal = terminal; + this.terminalHeight = terminal.getHeight(); + this.pagerEnabled = readPagerEnabled(configManagerProvider); + this.pagerCommand = readPagerCommand(configManagerProvider); + } + + /** + * Creates PagerSupport for testing. + * + * @param terminal JLine terminal (can be null for testing) + * @param terminalHeight terminal height in lines + * @param pagerEnabled whether pager is enabled + * @param pagerCommand pager command (null for default) + */ + PagerSupport(Terminal terminal, int terminalHeight, boolean pagerEnabled, String pagerCommand) { + this.terminal = terminal; + this.terminalHeight = terminalHeight; + this.pagerEnabled = pagerEnabled; + this.pagerCommand = resolveCommand(pagerCommand); + } + + /** + * Checks if the pager should be used for the given output. + * + * @param output the output to check + * @return true if the output exceeds terminal height and pager is enabled + */ + public boolean shouldUsePager(String output) { + if (!pagerEnabled) { + return false; + } + int lineCount = countLines(output); + int threshold = terminalHeight - TERMINAL_MARGIN; + return lineCount > threshold; + } + + /** + * Pipes the output through the configured pager. + * + * @param output the output to display in the pager + */ + public void pipeToPage(String output) { + String command = getPagerCommand(); + try { + ProcessBuilder pb = createPagerProcess(command); + Process process = pb.start(); + + try (OutputStream os = process.getOutputStream()) { + os.write(output.getBytes(StandardCharsets.UTF_8)); + } + + process.waitFor(); + } catch (IOException | InterruptedException e) { + // Fallback: print directly if pager fails + if (terminal != null) { + terminal.writer().print(output); + terminal.writer().flush(); + } + if (e instanceof InterruptedException) { + Thread.currentThread().interrupt(); + } + } + } + + /** + * Returns the pager command to use. + * + * @return the pager command + */ + public String getPagerCommand() { + return pagerCommand; + } + + /** + * Returns whether the pager is enabled. + * + * @return true if pager is enabled + */ + public boolean isPagerEnabled() { + return pagerEnabled; + } + + /** + * Counts the number of lines in the output. + * + * @param output the output to count lines in + * @return the number of lines + */ + int countLines(String output) { + if (output == null || output.isEmpty()) { + return 0; + } + // Remove trailing newline for accurate count + String normalized = output.endsWith("\n") ? output.substring(0, output.length() - 1) : output; Review Comment: I think `System.lineSeparator` should be used here and everywhere else, currently this doesn't seem to work on Windows. Actually, if you check the specific character then you will probably need to simply remove `\r` from the string. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
