add cat command. close #494

core/src/main/java/com/taobao/arthas/core/command/BuiltinCommandPack.java

@@ -1,5 +1,6 @@
 package com.taobao.arthas.core.command;
 
+import com.taobao.arthas.core.command.basic1000.CatCommand;
 import com.taobao.arthas.core.command.basic1000.ClsCommand;
 import com.taobao.arthas.core.command.basic1000.HelpCommand;
 import com.taobao.arthas.core.command.basic1000.HistoryCommand;
@@ -86,6 +87,7 @@ public class BuiltinCommandPack implements CommandResolver {
         commands.add(Command.create(SystemPropertyCommand.class));
         commands.add(Command.create(SystemEnvCommand.class));
         commands.add(Command.create(HistoryCommand.class));
+        commands.add(Command.create(CatCommand.class));
         commands.add(Command.create(PwdCommand.class));
     }
 }

core/src/main/java/com/taobao/arthas/core/command/basic1000/CatCommand.java

@@ -0,0 +1,150 @@
+package com.taobao.arthas.core.command.basic1000;
+
+import java.io.File;
+import java.io.IOException;
+import java.nio.charset.Charset;
+import java.util.ArrayList;
+import java.util.List;
+
+import com.taobao.arthas.core.shell.cli.CliToken;
+import com.taobao.arthas.core.shell.cli.Completion;
+import com.taobao.arthas.core.shell.cli.CompletionUtils;
+import com.taobao.arthas.core.shell.command.AnnotatedCommand;
+import com.taobao.arthas.core.shell.command.CommandProcess;
+import com.taobao.arthas.core.util.FileUtils;
+import com.taobao.arthas.core.util.LogUtil;
+import com.taobao.arthas.core.util.StringUtils;
+import com.taobao.middleware.cli.annotations.Argument;
+import com.taobao.middleware.cli.annotations.Description;
+import com.taobao.middleware.cli.annotations.Name;
+import com.taobao.middleware.cli.annotations.Option;
+import com.taobao.middleware.cli.annotations.Summary;
+import com.taobao.middleware.logger.Logger;
+
+@Name("cat")
+@Summary("Concatenate and print files")
+public class CatCommand extends AnnotatedCommand {
+    private static final Logger logger = LogUtil.getArthasLogger();
+    private List<String> files;
+    private String encoding;
+
+    @Argument(argName = "files", index = 0)
+    @Description("files")
+    public void setFiles(List<String> files) {
+        this.files = files;
+    }
+
+    @Option(longName = "encoding")
+    @Description("File encoding")
+    public void setEncoding(String encoding) {
+        this.encoding = encoding;
+    }
+
+    @Override
+    public void process(CommandProcess process) {
+        for (String file : files) {
+            File f = new File(file);
+            if (!f.exists()) {
+                process.write("cat " + file + ": No such file or directory\n");
+                process.end();
+                return;
+            }
+            if (f.isDirectory()) {
+                process.write("cat " + file + ": Is a directory\n");
+                process.end();
+                return;
+            }
+        }
+
+        for (String file : files) {
+            File f = new File(file);
+            if (f.length() > 1024 * 1024 * 8) {
+                process.write("cat " + file + ": Is to large, size: " + f.length() + '\n');
+                process.end();
+                return;
+            }
+            try {
+                String fileToString = FileUtils.readFileToString(f,
+                                encoding == null ? Charset.defaultCharset() : Charset.forName(encoding));
+                process.write(fileToString);
+            } catch (IOException e) {
+                logger.error(null, "cat read file error. name: " + file, e);
+                process.write("cat read file error: " + e.getMessage() + '\n');
+                process.end(1);
+                return;
+            }
+        }
+
+        process.end();
+    }
+
+    @Override
+    public void complete(Completion completion) {
+        List<CliToken> tokens = completion.lineTokens();
+        String token = tokens.get(tokens.size() - 1).value();
+
+        File dir = null;
+        String partName = "";
+        if (StringUtils.isBlank(token)) {
+            dir = new File("").getAbsoluteFile();
+            token = "";
+        } else if (token.endsWith("/")) {
+            dir = new File(token);
+        } else {
+            File parent = new File(token).getAbsoluteFile().getParentFile();
+            if (parent != null && parent.exists()) {
+                dir = parent;
+                partName = new File(token).getName();
+            }
+        }
+
+        File tokenFile = new File(token);
+
+        String tokenFileName = null;
+        if (token.endsWith("/")) {
+            tokenFileName = "";
+        } else {
+            tokenFileName = tokenFile.getName();
+        }
+
+        if (dir == null) {
+            super.complete(completion);
+            return;
+        }
+
+        File[] listFiles = dir.listFiles();
+
+        ArrayList<String> names = new ArrayList<String>();
+        for (File child : listFiles) {
+            if (child.getName().startsWith(partName)) {
+                if (child.isDirectory()) {
+                    names.add(child.getName() + "/");
+                } else {
+                    names.add(child.getName());
+                }
+            }
+        }
+
+        if (names.size() == 1 && names.get(0).endsWith("/")) {
+            String name = names.get(0);
+            // 这个函数补全后不会有空格，并且只能传入要补全的内容
+            completion.complete(name.substring(tokenFileName.length(), name.length()), false);
+            return;
+        }
+
+        String prefix = null;
+        if (token.endsWith("/")) {
+            prefix = token;
+        } else {
+            prefix = token.substring(0, token.length() - new File(token).getName().length());
+        }
+
+        ArrayList<String> namesWithPrefix = new ArrayList<String>();
+        for (String name : names) {
+            namesWithPrefix.add(prefix + name);
+        }
+        // 这个函数需要保留前缀
+        CompletionUtils.complete(completion, namesWithPrefix);
+    }
+
+}