VfsFolder

Supports a model a bit like CSS selectors, where a selection of operands is made before applying some operation. For example:

// count of files in this folder
auto count = folder.self.files;

// accumulated file byte-count
auto bytes = folder.self.bytes;

// a group of one folder (itself)
auto folders = folder.self;

The same approach is used to select the subtree descending from a folder:

// count of files in this tree
auto count = folder.tree.files;

// accumulated file byte-count
auto bytes = folder.tree.bytes;

// the group of child folders
auto folders = folder.tree;

Filtering can be applied to the tree resulting in a sub-group. Group operations remain applicable. Note that various wildcard characters may be used in the filtering:

// select a subset of the resultant tree
auto folders = folder.tree.subset("install");

// get total file bytes for a tree subset, using wildcards
auto bytes = folder.tree.subset("foo*").bytes;

Files are selected from a set of folders in a similar manner:

// files called "readme.txt" in this folder
auto count = folder.self.catalog("readme.txt").files;

// files called "read*.*" in this tree
auto count = folder.tree.catalog("read*.*").files;

// all txt files belonging to folders starting with "ins"
auto count = folder.tree.subset("ins*").catalog("*.txt").files;

// custom-filtered files within a subtree
auto count = folder.tree.catalog(&filter).files;

Sets of folders and files support iteration via foreach:

foreach (folder; root.tree)
         Stdout.formatln ("folder name:{}", folder.name);

foreach (folder; root.tree.subset("ins*"))
         Stdout.formatln ("folder name:{}", folder.name);

foreach (file; root.tree.catalog("*.d"))
         Stdout.formatln ("file name:{}", file.name);

Creating and opening a sub-folder is supported in a similar manner, where the single instance is 'selected' before the operation is applied. Open differs from create in that the folder must exist for the former:

root.folder("myNewFolder").create;

root.folder("myExistingFolder").open;

File manipulation is handled in much the same way:

root.file("myNewFile").create;

auto source = root.file("myExistingFile");
root.file("myCopiedFile").copy(source);

The principal benefits of these approaches are twofold: 1. it turns out to be notably more efficient in terms of traversal, and 2. there's no casting required, since there is a clean separation between files and folders.

See VfsFile for more information on file handling.