message_store

What a completed file operation can honestly say about what it changed.

One closed set rather than a set of independent booleans: the four states are mutually exclusive, and every consumer needs to agree on which one holds. Split across flags, a consumer that forgets one silently reports a change as fully displayed — which is how a delete whose pre-image was lost came to render identically to deleting an empty file.

• shown: diff and diff_stats describe the change. Also the state for a genuinely unchanged file and for operations that never compute a diff.
• untrusted_before: the pre-operation content could not be read, so before_content is a stand-in empty string. Any diff against it is fiction — an unchanged file looks like a no-op, a changed one like a whole-file insertion — so diff_stats is None and the body must not be rendered.
• unreadable_after: the operation succeeded but its result could not be read back, so there is nothing to diff. after_read_error carries the reason.
• terminators_only: the bytes changed but diff is None, because the change lives entirely in line terminators, which splitlines() discards.

Estimated terminal rows for a message whose rendered height is unknown.

Smallest useful row estimate for spacer and range-height math.

Line counts for a change, named so the pair cannot be swapped silently.

Keyword-only and frozen so that claim holds at construction as well as in transit: a positional pair is exactly the transposition this type exists to rule out, and the counts are read long after they are computed.

Types of messages in the chat.

Status of a tool call.

In-memory message data for virtualization.

This dataclass holds all information needed to recreate a message widget. It is designed to be lightweight so that thousands of messages can be stored without meaningful memory overhead.

Manages message data and widget window for virtualization.

This class stores all messages as data and manages a sliding window of widgets that are actually mounted in the DOM.