// NewNavigator constructs a new navigator object and waits indefinitely
// for commands sent to it. It sends an updated buffer whenever the
// navigator changes state.
// This function is meant to be run in a goroutine.
func NewNavigator(path string, commands <-chan string, buffers chan<- *view.Buffer) {
navigator := new(Navigator)
// Link the navigator up to the view.
navigator.view = buffers
// Set the initial working directory using
// the path passed in as an argument.
navigator.SetWorkingDirectory(path)
for {
select {
case command := <-commands: // A command has arrived.
// Invoke the command on the navigator.
switch command {
case "SelectNextEntry":
navigator.SelectNextEntry()
case "SelectLastEntry":
navigator.SelectLastEntry()
case "SelectPreviousEntry":
navigator.SelectPreviousEntry()
case "SelectFirstEntry":
navigator.SelectFirstEntry()
case "SortEntries":
navigator.SortEntries()
case "IntoSelectedEntry":
navigator.IntoSelectedEntry()
case "ToParentDirectory":
navigator.ToParentDirectory()
case "RemoveSelectedEntry":
navigator.RemoveSelectedEntry()
}
// Refresh the view.
buffers <- navigator.View(view.Height())
case directorySize := <-navigator.DirectorySizes: // A directory size calculation has completed.
// Update the stored entry size and flag it as calculated.
navigator.entries[directorySize.Index].Size = directorySize.Size
navigator.entries[directorySize.Index].SizeCalculated = true
// Reduce this count so the view increases the completion percentage.
navigator.pendingCalculations--
// Update the view, since we have another directory size.
navigator.view <- navigator.View(view.Height())
}
}
}
func (navigator *Navigator) populateEntries() {
var size int64
// Read the directory entries.
dirEntries, _ := ioutil.ReadDir(navigator.currentPath + "/")
navigator.entries = make([]*directory.Entry, len(dirEntries))
// Allocate a buffered channel on which we'll receive
// directory sizes from size-calculating goroutines.
navigator.DirectorySizes = make(chan *directory.EntrySize, len(dirEntries))
// Reset the number of pending calculations.
navigator.pendingCalculations = 0
for index, entry := range dirEntries {
entryInfo, _ := os.Stat(navigator.currentPath + "/" + entry.Name())
// Figure out the entry's size differently
// depending on whether or not it's a directory.
if entryInfo.IsDir() {
navigator.pendingCalculations++
// Calculate the directory's size asynchronously, passing the current
// index so that we know where to put the result when we receive it later on.
go directory.Size(navigator.currentPath+"/"+entry.Name(), index, navigator.DirectorySizes)
} else {
size = entryInfo.Size()
}
// Store the entry details.
navigator.entries[index] = &directory.Entry{Name: entry.Name(), Size: size, IsDirectory: entryInfo.IsDir(), SizeCalculated: !entryInfo.IsDir()}
}
// Update the view, since we have sizes for files.
navigator.view <- navigator.View(view.Height())
}