Documentation
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Overview ¶
Package live reads the sources of linked regions as they change: a file followed as it grows or is rewritten (File), and anything else that yields a table's rows over time behind the same Source.
A Source is polled on its owner's schedule, one poll at a time, from a goroutine of the owner's (a Bubble Tea command), and answers with an Update: rows to add, or all of them again, which the owner turns into a sheet.LiveOp for the region (Update.Op) and applies on the goroutine that owns the workbook. Sources never touch the workbook.
Index ¶
Constants ¶
const Interval = 250 * time.Millisecond
Interval is how often a followed source is polled.
Variables ¶
This section is empty.
Functions ¶
Types ¶
type File ¶
type File struct {
// Name is how the file is named to the user, in errors.
Name string
// Debounce is how long a file read whole must hold still.
Debounce time.Duration
// MaxRead bounds what one poll reads of a growing file, so a large
// file comes in over several polls, each a short step for the UI.
MaxRead int64
// Now is the clock; tests replace it.
Now func() time.Time
// contains filtered or unexported fields
}
File follows a file with the standard library's stat alone (no inotify or kqueue, which differ by OS and need cgo or a module), which polling every Interval makes cheap enough: one stat a poll while nothing changes.
A text table (CSV, TSV, JSON lines, NUON; fileio.Kind.Grows) is read as it grows: each poll reads what was appended, and a record cut off at the end waits for the rest (fileio.Tail). The file is read again whole when it shrinks (truncated), is another file (rotated: the path names a new inode), or its bytes before where reading stopped differ (rewritten in place). Any other format is read again whole when its size or modification time changes, once they have held still for Debounce, so a file being written isn't read half done.
func NewFile ¶
NewFile follows the file at path (on disk) in format k, with opt's table, query and locale (fileio.Options); name is how the user named it.
type Source ¶
type Source interface {
// Poll looks once for what changed since the last poll. It reports
// false when nothing did. Polls never overlap.
Poll(ctx context.Context) (Update, bool)
// Reload has the next poll read the table again, whole.
Reload()
// Close lets the source go; it is polled no more.
Close()
}
A Source yields a table's rows as they change.
type Update ¶
type Update struct {
// Reset has Rows replace every row; otherwise they follow the last.
Reset bool
// Header is the table's first row when it's new or changed.
Header sheet.LiveRow
Rows []sheet.LiveRow
// Err says why the source can't be read, "" once it can.
Err string
// Note says what was left out or changed in reading.
Note string
// More is set when more is waiting to be read at once, rather than
// after the next interval.
More bool
// At is when the poll found it.
At time.Time
}
Update is what a poll found.
Source Files