Struct StreamingWriter 

pub struct StreamingWriter<W> { /* private fields */ }

Streaming writer for output.

Controls streaming output with the following behaviors:

• Streaming formats (json, jsonl, csv, tsv): Output rows immediately.
• Non-streaming formats (table): Buffer rows up to buffer_limit.

Output Boundary

• Output started: When output_started == true (header has been written).
• Buffer overflow: Returns an error prompting --output json|csv|tsv or --limit.

Implementations

impl<W: Write> StreamingWriter<W>

pub fn new( writer: W, formatter: Box<dyn Formatter>, columns: Vec<Column>, limit: Option<usize>, ) -> Self

Create a new StreamingWriter.

Arguments

• writer - The output writer (e.g., stdout).
• formatter - The formatter to use for output.
• columns - Column definitions for the output.
• limit - Optional row limit.

pub fn with_buffer_limit(self, buffer_limit: usize) -> Self

Create a new StreamingWriter with a custom buffer limit.

pub fn with_quiet(self, quiet: bool) -> Self

Enable quiet mode (suppress warnings).

pub fn is_quiet(&self) -> bool

Check if quiet mode is enabled.

When quiet mode is enabled, status-only output (OK messages) should be suppressed.

pub fn prepare(&mut self, row_count_hint: Option<usize>) -> Result<()>

Prepare the writer for output.

For streaming formats (json, jsonl, csv, tsv), immediately outputs the header. For non-streaming formats (table), defers header output.

Arguments

• row_count_hint - Optional estimated row count (unused for buffer sizing).

pub fn write_row(&mut self, row: Row) -> Result<WriteStatus>

Write a row to the output.

For streaming formats, the row is output immediately. For non-streaming formats, the row is buffered.

Returns

• WriteStatus::Continue - Row was written, continue writing.
• WriteStatus::LimitReached - Row limit reached, stop writing.

Note

The row is taken by ownership to avoid unnecessary cloning when buffering.

pub fn finish(&mut self) -> Result<()>

Finish output, flushing any buffered rows and writing the footer.

pub fn written_count(&self) -> usize

Returns the number of rows written.

pub fn output_started(&self) -> bool

Returns whether output has started.

pub fn buffered_bytes(&self) -> usize

Returns approximate buffered bytes.