rhg: add a `DebugData` `Command` to prepare the `rhg debugdata` subcommand

Differential Revision: https://phab.mercurial-scm.org/D8960

rust/rhg/src/commands/debugdata.rs

@@ -0,0 +1,80 b''
+use crate::commands::Command;
+use crate::error::{CommandError, CommandErrorKind};
+use crate::ui::utf8_to_local;
+use crate::ui::Ui;
+use hg::operations::{
+    DebugData, DebugDataError, DebugDataErrorKind, DebugDataKind,
+};
+
+pub const HELP_TEXT: &str = "
+Dump the contents of a data file revision
+";
+
+pub struct DebugDataCommand<'a> {
+    rev: &'a str,
+    kind: DebugDataKind,
+}
+
+impl<'a> DebugDataCommand<'a> {
+    pub fn new(rev: &'a str, kind: DebugDataKind) -> Self {
+        DebugDataCommand { rev, kind }
+    }
+}
+
+impl<'a> Command for DebugDataCommand<'a> {
+    fn run(&self, ui: &Ui) -> Result<(), CommandError> {
+        let mut operation = DebugData::new(self.rev, self.kind);
+        let data =
+            operation.run().map_err(|e| to_command_error(self.rev, e))?;
+
+        let mut stdout = ui.stdout_buffer();
+        stdout.write_all(&data)?;
+        stdout.flush()?;
+
+        Ok(())
+    }
+}
+
+/// Convert operation errors to command errors
+fn to_command_error(rev: &str, err: DebugDataError) -> CommandError {
+    match err.kind {
+        DebugDataErrorKind::FindRootError(err) => CommandError::from(err),
+        DebugDataErrorKind::IoError(err) => CommandError {
+            kind: CommandErrorKind::Abort(Some(
+                utf8_to_local(&format!("abort: {}\n", err)).into(),
+            )),
+        },
+        DebugDataErrorKind::InvalidRevision => CommandError {
+            kind: CommandErrorKind::Abort(Some(
+                utf8_to_local(&format!(
+                    "abort: invalid revision identifier{}\n",
+                    rev
+                ))
+                .into(),
+            )),
+        },
+        DebugDataErrorKind::UnsuportedRevlogVersion(version) => CommandError {
+            kind: CommandErrorKind::Abort(Some(
+                utf8_to_local(&format!(
+                    "abort: unsupported revlog version {}\n",
+                    version
+                ))
+                .into(),
+            )),
+        },
+        DebugDataErrorKind::CorruptedRevlog => CommandError {
+            kind: CommandErrorKind::Abort(Some(
+                "abort: corrupted revlog\n".into(),
+            )),
+        },
+        DebugDataErrorKind::UnknowRevlogDataFormat(format) => CommandError {
+            kind: CommandErrorKind::Abort(Some(
+                utf8_to_local(&format!(
+                    "abort: unknow revlog dataformat {:?}\n",
+                    format
+                ))
+                .into(),
+            )),
+        },
+    }
+}

rust/hg-core/src/operations/mod.rs

@@ -1,18 +1,21 b''
 //! A distinction is made between operations and commands.
 //! An operation is what can be done whereas a command is what is exposed by
 //! the cli. A single command can use several operations to achieve its goal.
 
 mod debugdata;
 mod dirstate_status;
 mod find_root;
 mod list_tracked_files;
+pub use debugdata::{
+    DebugData, DebugDataError, DebugDataErrorKind, DebugDataKind,
+};
 pub use find_root::{FindRoot, FindRootError, FindRootErrorKind};
 pub use list_tracked_files::{
     ListTrackedFiles, ListTrackedFilesError, ListTrackedFilesErrorKind,
 };
 
 // TODO add an `Operation` trait when GAT have landed (rust #44265):
 // there is no way to currently define a trait which can both return
 // references to `self` and to passed data, which is what we would need.
 // Generic Associated Types may fix this and allow us to have a unified
 // interface.

rust/rhg/src/commands.rs

@@ -1,11 +1,12 b''
+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/ui.rs

@@ -1,105 +1,113 b''
+use std::borrow::Cow;
 use std::io;
 use std::io::{ErrorKind, Write};
 
 #[derive(Debug)]
 pub struct Ui {
     stdout: std::io::Stdout,
     stderr: std::io::Stderr,
 }
 
 /// The kind of user interface error
 pub enum UiError {
     /// The standard output stream cannot be written to
     StdoutError(io::Error),
     /// The standard error stream cannot be written to
     StderrError(io::Error),
 }
 
 /// The commandline user interface
 impl Ui {
     pub fn new() -> Self {
         Ui {
             stdout: std::io::stdout(),
             stderr: std::io::stderr(),
         }
     }
 
     /// Returns a buffered handle on stdout for faster batch printing
     /// operations.
     pub fn stdout_buffer(&self) -> StdoutBuffer<std::io::StdoutLock> {
         StdoutBuffer::new(self.stdout.lock())
     }
 
     /// Write bytes to stdout
     pub fn write_stdout(&self, bytes: &[u8]) -> Result<(), UiError> {
         let mut stdout = self.stdout.lock();
 
         stdout.write_all(bytes).or_else(handle_stdout_error)?;
 
         stdout.flush().or_else(handle_stdout_error)
     }
 
     /// Write bytes to stderr
     pub fn write_stderr(&self, bytes: &[u8]) -> Result<(), UiError> {
         let mut stderr = self.stderr.lock();
 
         stderr.write_all(bytes).or_else(handle_stderr_error)?;
 
         stderr.flush().or_else(handle_stderr_error)
     }
 
     /// Write string line to stderr
     pub fn writeln_stderr_str(&self, s: &str) -> Result<(), UiError> {
         self.write_stderr(&format!("{}\n", s).as_bytes())
     }
 }
 
 /// A buffered stdout writer for faster batch printing operations.
 pub struct StdoutBuffer<W: Write> {
     buf: io::BufWriter<W>,
 }
 
 impl<W: Write> StdoutBuffer<W> {
     pub fn new(writer: W) -> Self {
         let buf = io::BufWriter::new(writer);
         Self { buf }
     }
 
     /// Write bytes to stdout buffer
     pub fn write_all(&mut self, bytes: &[u8]) -> Result<(), UiError> {
         self.buf.write_all(bytes).or_else(handle_stdout_error)
     }
 
     /// Flush bytes to stdout
     pub fn flush(&mut self) -> Result<(), UiError> {
         self.buf.flush().or_else(handle_stdout_error)
     }
 }
 
 /// Sometimes writing to stdout is not possible, try writing to stderr to
 /// signal that failure, otherwise just bail.
 fn handle_stdout_error(error: io::Error) -> Result<(), UiError> {
     if let ErrorKind::BrokenPipe = error.kind() {
         // This makes `| head` work for example
         return Ok(());
     }
     let mut stderr = io::stderr();
 
     stderr
         .write_all(&[b"abort: ", error.to_string().as_bytes(), b"\n"].concat())
         .map_err(UiError::StderrError)?;
 
     stderr.flush().map_err(UiError::StderrError)?;
 
     Err(UiError::StdoutError(error))
 }
 
 /// Sometimes writing to stderr is not possible.
 fn handle_stderr_error(error: io::Error) -> Result<(), UiError> {
     // A broken pipe should not result in a error
     // like with `| head` for example
     if let ErrorKind::BrokenPipe = error.kind() {
         return Ok(());
     }
     Err(UiError::StdoutError(error))
 }
+
+/// Encode rust strings according to the user system.
+pub fn utf8_to_local(s: &str) -> Cow<[u8]> {
+    // TODO encode for the user's system //
+    let bytes = s.as_bytes();
+    Cow::Borrowed(bytes)
+}