mako-tree

mako-tree

The build tree structure used internally by mako

Overview

When working with mako build hooks, the first 2 arguments will be the current file and the build tree respectively. Currently, both of those APIs are contained in this module, as they tightly coupled and don't make much sense on their own. (at least at the current time)

Throughout the "analyze" phase, a tree is being built up, starting from the list of entry files. Each file being processed adds any direct dependencies, which will then recursively be processed to find more dependencies. Each vertex in the graph corresponds to some sort of input file.

During the "build" phase, the tree may be trimmed down, such as the case where the entire dependency chain for a JS file will be combined into a single output file. By the end of the build, each vertex in the graph corresponds to an output file.

API

As mako continues to be developed and evolve, some documentation and guides dedicated to plugin authors will surface. For now, the following is purely the API available to both the file and tree parameters in plugins/hooks.

The Tree constructor (documented below) is the primary export for the module. It must be used with the new keyword.

var Tree = require('mako-tree');
var tree = new Tree();

Tree() (constructor)

Each instance represents a build tree. Internally, a graph is used to manage the relationships between all the files being tracked.

NOTE: All paths are assumed to be absolute, this library makes no attempt to set a base/root directory and maintain relative paths.

Tree#hasFile(location)

Returns a Boolean reflecting if the file at the given location exists in this tree.

Tree#addFile(location)

Adds a file at the given location to the tree, if it is not already present, and returns the corresponding File instance.

Tree#getFile(location)

Returns the File instance for the file at the given location. It is assumed to already be part of the graph, and will throw an error if not found.

Tree#removeFile(location)

Removes the file at the given location from the tree. To successfully remove a file, it must not be depended on by another file. This is mostly a plumbing function, and plugin authors are likely going to use removeDependency() instead.

Tree#isSource(location)

Returns a Boolean telling whether or not the file at location is an entry file. (in other words, is not a dependency)

Tree#getEntries([from])

Returns an Array of all the entry files in this graph. (in other words, files that are at the end of the dependency chains)

If from is provided, the returned list will only include entries that are reachable from that specified file.

Tree#hasDependency(parent, child)

Returns a Boolean reflecting if the dependency relationship between parent and child already exists in the tree.

Tree#addDependency(parent, child)

Adds a new dependency relationship to the graph setting parent as depending on child. If child is not already part of the tree, it will be added. (however, if parent is not in the tree, that is assumed to be an error) This will return the File instance for the child file.

Tree#removeDependency(parent, child)

Removes the specified dependency relationship, basically saying that parent no longer depends on child)

NOTE: If no other files depend on child, it will be removed from the tree. This allows plugins to only concern themselves with the relationships they are aware of, leaving the overall tree management to mako.

Tree#dependenciesOf(file, [recursive])

Returns an Array of files that are dependencies of the given file.

By default, it will only return the direct descendants, but adding recursive will return a flat list of all the files down the entire dependency chain.

Tree#dependantsOf(file, [recursive])

Returns an Array of files that depend on the given file.

By default, it will only return the direct ancestors, but adding recursive will return a flat list of all the files up the entire dependency chain.

Tree#topologicalOrder()

Returns an Array of files that can be processed in an order that respects all the dependencies.

Tree#clone()

Returns a new Tree object that is an effective clone of the original.

Tree#prune([entries])

Removes any orphaned files from the graph. A file is considered orphaned if it has no path to any file marked as an entry.

If entries is passed, (must be an Array) then any files that cannot reach those files will be removed from the graph. (essentially overrides the internal list of entries)

File(location, tree, [entry]) (constructor)

Each instance represents a file in the overall build. The location is an absolute path, tree is the tree that contains this particular file and entry flags a file as an entry.

Entry files are uniquely handled, particularly when it comes to Tree#prune(). Any files that do not have a path to some entry file are considered orphaned, and will be pruned.

File#path

The absolute path to where this file exists on disk.

File#type

The current file type associated with this file. This value is used to determine what plugins/hooks need to be invoked at various stages.

NOTE: plugins can modify this value if their work changes the file type. (such as compiling coffee into js)

File#contents

This holds the current contents of the file. When first read, this property should be set, and subsequent changes to the source code should apply to this property.

NOTE: must be set by a plugin.

File#output

The absolute path to where this file should be written on disk.

NOTE: must be set by a plugin.

File#analyzing

An internal flag that helps mako know when a particular file is currently being analyzed. (to prevent race conditions and duplicating efforts) There is currently no public use for this property.

File#analyzed

A flag that helps mako know when a particular file has already been analyzed, so it doesn't continuously analyze the same file during subsequent builds. Do not change this manually, instead use File#dirty().

File#isEntry()

Short-hand for tree.isEntry(file.path).

File#hasDependency(child)

Short-hand for tree.hasDependency(file.path, child).

File#addDependency(child)

Short-hand for tree.addDependency(file.path, child).

File#removeDependency(child)

Short-hand for tree.removeDependency(file.path, child).

File#dependencies([recursive])

Short-hand for tree.dependenciesOf(file.path, recursive).

File#dependants([recursive])

Short-hand for tree.dependantsOf(file.path, recursive).

File#dirty()

Can be used by the prewrite hook to mark a file as "dirty" so that it should be analyzed again.

For example, mako-stat will use this method whenever the modification time for a file has changed, which indicates to mako that analyze needs to be run again for this file.

File#clone(tree)

Returns a new File object that is an effective clone of the original.