rhg: add a limited `rhg cat -r` subcommand

It only supports revision specification (rev or full hash) and the list of files
to cat.

Differential Revision: https://phab.mercurial-scm.org/D9052

rust/rhg/src/commands/cat.rs

@@ -0,0 +1,99 b''
+use crate::commands::Command;
+use crate::error::{CommandError, CommandErrorKind};
+use crate::ui::utf8_to_local;
+use crate::ui::Ui;
+use hg::operations::FindRoot;
+use hg::operations::{CatRev, CatRevError, CatRevErrorKind};
+use hg::utils::hg_path::HgPathBuf;
+use micro_timer::timed;
+use std::convert::TryFrom;
+
+pub const HELP_TEXT: &str = "
+Output the current or given revision of files
+";
+
+pub struct CatCommand<'a> {
+    rev: Option<&'a str>,
+    files: Vec<&'a str>,
+}
+
+impl<'a> CatCommand<'a> {
+    pub fn new(rev: Option<&'a str>, files: Vec<&'a str>) -> Self {
+        Self { rev, files }
+    }
+
+    fn display(&self, ui: &Ui, data: &[u8]) -> Result<(), CommandError> {
+        ui.write_stdout(data)?;
+        Ok(())
+    }
+}
+
+impl<'a> Command for CatCommand<'a> {
+    #[timed]
+    fn run(&self, ui: &Ui) -> Result<(), CommandError> {
+        let root = FindRoot::new().run()?;
+        let cwd = std::env::current_dir()
+            .or_else(|e| Err(CommandErrorKind::CurrentDirNotFound(e)))?;
+
+        let mut files = vec![];
+        for file in self.files.iter() {
+            let normalized = cwd.join(&file);
+            let stripped = normalized
+                .strip_prefix(&root)
+                .map_err(|_| CommandErrorKind::Abort(None))?;
+            let hg_file = HgPathBuf::try_from(stripped.to_path_buf())
+                .map_err(|_| CommandErrorKind::Abort(None))?;
+            files.push(hg_file);
+        }
+
+        match self.rev {
+            Some(rev) => {
+                let mut operation = CatRev::new(&root, rev, &files)
+                    .map_err(|e| map_rev_error(rev, e))?;
+                let data =
+                    operation.run().map_err(|e| map_rev_error(rev, e))?;
+                self.display(ui, &data)
+            }
+            None => Err(CommandErrorKind::Unimplemented.into()),
+        }
+    }
+}
+
+/// Convert `CatRevErrorKind` to `CommandError`
+fn map_rev_error(rev: &str, err: CatRevError) -> CommandError {
+    CommandError {
+        kind: match err.kind {
+            CatRevErrorKind::IoError(err) => CommandErrorKind::Abort(Some(
+                utf8_to_local(&format!("abort: {}\n", err)).into(),
+            )),
+            CatRevErrorKind::InvalidRevision => CommandErrorKind::Abort(Some(
+                utf8_to_local(&format!(
+                    "abort: invalid revision identifier{}\n",
+                    rev
+                ))
+                .into(),
+            )),
+            CatRevErrorKind::UnsuportedRevlogVersion(version) => {
+                CommandErrorKind::Abort(Some(
+                    utf8_to_local(&format!(
+                        "abort: unsupported revlog version {}\n",
+                        version
+                    ))
+                    .into(),
+                ))
+            }
+            CatRevErrorKind::CorruptedRevlog => CommandErrorKind::Abort(Some(
+                "abort: corrupted revlog\n".into(),
+            )),
+            CatRevErrorKind::UnknowRevlogDataFormat(format) => {
+                CommandErrorKind::Abort(Some(
+                    utf8_to_local(&format!(
+                        "abort: unknow revlog dataformat {:?}\n",
+                        format
+                    ))
+                    .into(),
+                ))
+            }
+        },
+    }
+}

rust/rhg/src/commands.rs

@@ -1,12 +1,13 b''
+pub mod cat;
 pub mod debugdata;
 pub mod files;
 pub mod root;
 use crate::error::CommandError;
 use crate::ui::Ui;
 
 /// The common trait for rhg commands
 ///
 /// Normalize the interface of the commands provided by rhg
 pub trait Command {
     fn run(&self, ui: &Ui) -> Result<(), CommandError>;
 }

rust/rhg/src/error.rs

@@ -1,110 +1,113 b''
 use crate::exitcode;
 use crate::ui::UiError;
 use hg::operations::{FindRootError, FindRootErrorKind};
 use hg::utils::files::get_bytes_from_path;
 use std::convert::From;
 use std::path::PathBuf;
 
 /// The kind of command error
 #[derive(Debug)]
 pub enum CommandErrorKind {
     /// The root of the repository cannot be found
     RootNotFound(PathBuf),
     /// The current directory cannot be found
     CurrentDirNotFound(std::io::Error),
     /// The standard output stream cannot be written to
     StdoutError,
     /// The standard error stream cannot be written to
     StderrError,
     /// The command aborted
     Abort(Option<Vec<u8>>),
+    /// A mercurial capability as not been implemented.
+    Unimplemented,
 }
 
 impl CommandErrorKind {
     pub fn get_exit_code(&self) -> exitcode::ExitCode {
         match self {
             CommandErrorKind::RootNotFound(_) => exitcode::ABORT,
             CommandErrorKind::CurrentDirNotFound(_) => exitcode::ABORT,
             CommandErrorKind::StdoutError => exitcode::ABORT,
             CommandErrorKind::StderrError => exitcode::ABORT,
             CommandErrorKind::Abort(_) => exitcode::ABORT,
+            CommandErrorKind::Unimplemented => exitcode::UNIMPLEMENTED_COMMAND,
         }
     }
 
     /// Return the message corresponding to the error kind if any
     pub fn get_error_message_bytes(&self) -> Option<Vec<u8>> {
         match self {
             // TODO use formating macro
             CommandErrorKind::RootNotFound(path) => {
                 let bytes = get_bytes_from_path(path);
                 Some(
                     [
                         b"abort: no repository found in '",
                         bytes.as_slice(),
                         b"' (.hg not found)!\n",
                     ]
                     .concat(),
                 )
             }
             // TODO use formating macro
             CommandErrorKind::CurrentDirNotFound(e) => Some(
                 [
                     b"abort: error getting current working directory: ",
                     e.to_string().as_bytes(),
                     b"\n",
                 ]
                 .concat(),
             ),
             CommandErrorKind::Abort(message) => message.to_owned(),
             _ => None,
         }
     }
 }
 
 /// The error type for the Command trait
 #[derive(Debug)]
 pub struct CommandError {
     pub kind: CommandErrorKind,
 }
 
 impl CommandError {
     /// Exist the process with the corresponding exit code.
     pub fn exit(&self) {
         std::process::exit(self.kind.get_exit_code())
     }
 
     /// Return the message corresponding to the command error if any
     pub fn get_error_message_bytes(&self) -> Option<Vec<u8>> {
         self.kind.get_error_message_bytes()
     }
 }
 
 impl From<CommandErrorKind> for CommandError {
     fn from(kind: CommandErrorKind) -> Self {
         CommandError { kind }
     }
 }
 
 impl From<UiError> for CommandError {
     fn from(error: UiError) -> Self {
         CommandError {
             kind: match error {
                 UiError::StdoutError(_) => CommandErrorKind::StdoutError,
                 UiError::StderrError(_) => CommandErrorKind::StderrError,
             },
         }
     }
 }
 
 impl From<FindRootError> for CommandError {
     fn from(err: FindRootError) -> Self {
         match err.kind {
             FindRootErrorKind::RootNotFound(path) => CommandError {
                 kind: CommandErrorKind::RootNotFound(path),
             },
             FindRootErrorKind::GetCurrentDirError(e) => CommandError {
                 kind: CommandErrorKind::CurrentDirNotFound(e),
             },
         }
     }
 }

rust/rhg/src/main.rs

@@ -1,141 +1,177 b''
 extern crate log;
 use clap::App;
 use clap::AppSettings;
 use clap::Arg;
 use clap::ArgGroup;
 use clap::ArgMatches;
 use clap::SubCommand;
 use hg::operations::DebugDataKind;
 use std::convert::TryFrom;
 
 mod commands;
 mod error;
 mod exitcode;
 mod ui;
 use commands::Command;
 use error::CommandError;
 
 fn main() {
     env_logger::init();
     let app = App::new("rhg")
         .setting(AppSettings::AllowInvalidUtf8)
         .setting(AppSettings::SubcommandRequired)
         .setting(AppSettings::VersionlessSubcommands)
         .version("0.0.1")
         .subcommand(
             SubCommand::with_name("root").about(commands::root::HELP_TEXT),
         )
         .subcommand(
             SubCommand::with_name("files")
                 .arg(
                     Arg::with_name("rev")
                         .help("search the repository as it is in REV")
                         .short("-r")
                         .long("--revision")
                         .value_name("REV")
                         .takes_value(true),
                 )
                 .about(commands::files::HELP_TEXT),
         )
         .subcommand(
+            SubCommand::with_name("cat")
+                .arg(
+                    Arg::with_name("rev")
+                        .help("search the repository as it is in REV")
+                        .short("-r")
+                        .long("--revision")
+                        .value_name("REV")
+                        .takes_value(true),
+                )
+                .arg(
+                    clap::Arg::with_name("files")
+                        .required(true)
+                        .multiple(true)
+                        .empty_values(false)
+                        .value_name("FILE")
+                        .help("Activity to start: activity@category"),
+                )
+                .about(commands::cat::HELP_TEXT),
+        )
+        .subcommand(
             SubCommand::with_name("debugdata")
                 .about(commands::debugdata::HELP_TEXT)
                 .arg(
                     Arg::with_name("changelog")
                         .help("open changelog")
                         .short("-c")
                         .long("--changelog"),
                 )
                 .arg(
                     Arg::with_name("manifest")
                         .help("open manifest")
                         .short("-m")
                         .long("--manifest"),
                 )
                 .group(
                     ArgGroup::with_name("")
                         .args(&["changelog", "manifest"])
                         .required(true),
                 )
                 .arg(
                     Arg::with_name("rev")
                         .help("revision")
                         .required(true)
                         .value_name("REV"),
                 ),
         );
 
     let matches = app.clone().get_matches_safe().unwrap_or_else(|err| {
         let _ = ui::Ui::new().writeln_stderr_str(&err.message);
         std::process::exit(exitcode::UNIMPLEMENTED_COMMAND)
     });
 
     let ui = ui::Ui::new();
 
     let command_result = match_subcommand(matches, &ui);
 
     match command_result {
         Ok(_) => std::process::exit(exitcode::OK),
         Err(e) => {
             let message = e.get_error_message_bytes();
             if let Some(msg) = message {
                 match ui.write_stderr(&msg) {
                     Ok(_) => (),
                     Err(_) => std::process::exit(exitcode::ABORT),
                 };
             };
             e.exit()
         }
     }
 }
 
 fn match_subcommand(
     matches: ArgMatches,
     ui: &ui::Ui,
 ) -> Result<(), CommandError> {
     match matches.subcommand() {
         ("root", _) => commands::root::RootCommand::new().run(&ui),
         ("files", Some(matches)) => {
             commands::files::FilesCommand::try_from(matches)?.run(&ui)
         }
+        ("cat", Some(matches)) => {
+            commands::cat::CatCommand::try_from(matches)?.run(&ui)
+        }
         ("debugdata", Some(matches)) => {
             commands::debugdata::DebugDataCommand::try_from(matches)?.run(&ui)
         }
         _ => unreachable!(), // Because of AppSettings::SubcommandRequired,
     }
 }
 
 impl<'a> TryFrom<&'a ArgMatches<'_>> for commands::files::FilesCommand<'a> {
     type Error = CommandError;
 
     fn try_from(args: &'a ArgMatches) -> Result<Self, Self::Error> {
         let rev = args.value_of("rev");
         Ok(commands::files::FilesCommand::new(rev))
     }
 }
 
+impl<'a> TryFrom<&'a ArgMatches<'_>> for commands::cat::CatCommand<'a> {
+    type Error = CommandError;
+
+    fn try_from(args: &'a ArgMatches) -> Result<Self, Self::Error> {
+        let rev = args.value_of("rev");
+        let files = match args.values_of("files") {
+            Some(files) => files.collect(),
+            None => vec![],
+        };
+        Ok(commands::cat::CatCommand::new(rev, files))
+    }
+}
+
 impl<'a> TryFrom<&'a ArgMatches<'_>>
     for commands::debugdata::DebugDataCommand<'a>
 {
     type Error = CommandError;
 
     fn try_from(args: &'a ArgMatches) -> Result<Self, Self::Error> {
         let rev = args
             .value_of("rev")
             .expect("rev should be a required argument");
         let kind = match (
             args.is_present("changelog"),
             args.is_present("manifest"),
         ) {
             (true, false) => DebugDataKind::Changelog,
             (false, true) => DebugDataKind::Manifest,
             (true, true) => {
                 unreachable!("Should not happen since options are exclusive")
             }
             (false, false) => {
                 unreachable!("Should not happen since options are required")
             }
         };
         Ok(commands::debugdata::DebugDataCommand::new(rev, kind))
     }
 }