71 lines
2.1 KiB
Go
71 lines
2.1 KiB
Go
// 28 july 2014
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package ui
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import (
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"fmt"
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"reflect"
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"sync"
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)
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// Table is a Control that displays a list of like-structured data in a grid where each row represents an item and each column represents a bit of data.
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// As such, a Table renders a []struct{...} where each field of the struct is rendered using package fmt's %v rule.
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// Tables maintain their own storage behind a sync.RWMutex-compatible sync.Locker; use Table.Lock()/Table.Unlock() to make changes and Table.RLock()/Table.RUnlock() to merely read values.
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type Table interface {
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Control
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// Lock and Unlock lock and unlock Data for reading or writing.
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// RLock and RUnlock lock and unlock Data for reading only.
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// These methods have identical semantics to the analogous methods of sync.RWMutex.
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// In addition, Unlock() will request an update of the Table to account for whatever was changed.
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Lock()
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Unlock()
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RLock()
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RUnlock()
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// Data returns the internal data.
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// The returned value will contain an object of type pointer to slice of some structure; use a type assertion to get the properly typed object out.
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// Do not call this outside a Lock()..Unlock() or RLock()..RUnlock() pair.
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Data() interface{}
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}
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type tablebase struct {
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lock sync.RWMutex
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data interface{}
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}
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// NewTable creates a new Table.
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// Currently, the argument must be a reflect.Type representing the structure that each item in the Table will hold, and the Table will be initially empty.
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// This will change in the future.
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func NewTable(ty reflect.Type) Table {
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if ty.Kind() != reflect.Struct {
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panic(fmt.Errorf("unknown or unsupported type %v given to NewTable()", ty))
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}
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b := new(tablebase)
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// we want a pointer to a slice
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b.data = reflect.New(reflect.SliceOf(ty)).Interface()
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return finishNewTable(b, ty)
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}
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func (b *tablebase) Lock() {
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b.lock.Lock()
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}
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// Unlock() is defined on each backend implementation of Table
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// they should all call this, however
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func (b *tablebase) unlock() {
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b.lock.Unlock()
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}
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func (b *tablebase) RLock() {
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b.lock.RLock()
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}
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func (b *tablebase) RUnlock() {
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b.lock.RUnlock()
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}
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func (b *tablebase) Data() interface{} {
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return b.data
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}
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