Struct XTrace 

pub struct XTrace { /* private fields */ }

Collection of temporary string buffers that accumulate expanded strings

See the module documentation for details.

An XTrace contains four string buffers that accumulate each of the following:

• Command words (command name and arguments)
• Assignments
• Redirections
• Here-document contents

The finish function creates the final string to be printed.

Implementations

impl XTrace

pub fn new() -> Self

Creates a new trace buffer.

pub fn from_options(options: &OptionSet) -> Option<Self>

Creates a new trace buffer if the xtrace option is on.

If the option is off, this function returns None.

pub fn words(&mut self) -> &mut (impl Write + use<>)

Returns a reference to the words buffer.

The words buffer is for tracing command words. When writing to the buffer, the content should end with a space.

pub fn assigns(&mut self) -> &mut (impl Write + use<>)

Returns a reference to the assignments buffer.

The assignments buffer is for tracing assignments. When writing to the buffer, the content should end with a space.

pub fn redirs(&mut self) -> &mut (impl Write + use<>)

Returns a reference to the redirections buffer.

The redirections buffer is for tracing redirections. When writing to the buffer, the content should end with a space.

You should not write the contents of here-documents to this buffer. See also here_doc_contents.

pub fn here_doc_contents(&mut self) -> &mut (impl Write + use<>)

Returns a reference to the here-document contents buffer.

You should write the contents of here-documents you wrote to the redirections buffer.

pub fn clear(&mut self)

Clears the buffer contents.

pub fn is_empty(&self) -> bool

Returns whether all the buffers are empty.

pub async fn finish(&self, env: &mut Env) -> String

Constructs the final trace to be printed to stderr.

If all the buffers are empty, the result is empty. Otherwise, the result is the concatenation of the following:

• The expansion of $PS4
• The concatenation of the assigns, words, and redirs buffers with trailing spaces trimmed and a newline appended
• The here_doc_contents buffer

If $PS4 fails to expand, this function prints an error message and uses the variable value intact.

If this function is called while $PS4 is being expanded inside this function, the expansion of $PS4 is skipped and an empty string is returned. This prevents infinite recursion when $PS4 contains a command substitution that causes XTrace::finish to be called again.

Trait Implementations

impl Clone for XTrace

fn clone(&self) -> XTrace

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for XTrace

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for XTrace

fn default() -> XTrace

Returns the “default value” for a type.

impl Hash for XTrace

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl PartialEq for XTrace

fn eq(&self, other: &XTrace) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Eq for XTrace

impl StructuralPartialEq for XTrace