附录 F. 实现细节
This appendix contains a more detailed discussion of the implementation of some of TortoiseSVN's features.
file and folder has a Subversion status value as reported by the
Subversion library. In the command line client, these are represented
by single letter codes, but in TortoiseSVN they are shown graphically
using the icon overlays. Because the number of overlays is very
limited, each overlay may represent one of several status values.
The Conflicted overlay is used to represent the
state, where an update or switch results in conflicts between local
changes and changes downloaded from the repository. It is also used to
obstructed state, which can occur when an operation is unable to complete.
The Modified overlay represents the
modified state, where you have made local modifications, the
merged state, where changes from the repository have been merged with local changes, and the
replaced state, where a file has been deleted and replaced by another different file with the same name.
The Deleted overlay represents the
deleted state, where an item is scheduled for deletion, or the
state, where an item is not present. Naturally an item which is
missing cannot have an overlay itself, but the parent folder can be
marked if one of its child items is missing.
The Added overlay is simply used to represent the
added status when an item has been added to version control.
The In Subversion overlay is used to represent an item which is in the
state, or a versioned item whose state is not yet known. Because
TortoiseSVN uses a background caching process to gather status, it may
take a few seconds before the overlay updates.
The Needs Lock overlay is used to indicate when a file has the
svn:needs-lock property set. For working copies which were created using Subversion 1.4.0 and later, the
status is cached locally by Subversion and this is used to determine
when to show this overlay. For working copies which are in pre-1.4.x
format, TortoiseSVN shows this overlay when the file has read-only
status. Note that Subversion automatically upgrades working copies when
you update them, although the caching of the
svn:needs-lock property may not happen until the file itself is updated.
The Ignored overlay is used to represent an item which is in the
ignored state, either due to a global ignore pattern, or the
svn:ignore property of the parent folder. This overlay is optional.
The Unversioned overlay is used to represent an item which is in the
unversioned state. This is an item in a versioned folder, but which is not under version control itself. This overlay is optional.
If an item has subversion status
none (the item is not within a working copy) then no overlay is shown. If you have chosen to disable the Ignored and Unversioned overlays then no overlay will be shown for those files either.
每个条目只有一个 Subversion 状态。例如一个文件可以被本地修改，同时被标记为删除。Subversion 返回一个状态 – 即
已经删除。这些优先级是 Subversion 自己定义的。
当 TortoiseSVN 递归显示状态时(默认配置)，每个目录用重载图标显示自己的状态和所有子孙的状态。为了显示单个概要重载，我们使用上述优先级决定使用哪个重载，冲突重载使用最高优先级。
fact, you may find that not all of these icons are used on your
system. This is because the number of overlays allowed by Windows is
limited to 15. Windows uses 4 of those, and the remaining 11 can be
used by other applications. If there are not enough overlay slots
available, TortoiseSVN tries to be a “Good Citizen (TM)” and limits its
use of overlays to give other apps a chance.
Normal, Modified and Conflicted are always loaded and visible.
Deleted is loaded if possible, but falls back to Modified if there are not enough slots.
Read-Only is loaded if possible, but falls back to Normal if there are not enough slots.
Locked is only loaded if there are fewer than 13 overlays already loaded. It falls back to Normal if there are not enough slots.
Added is only loaded if there are fewer than 14 overlays already loaded. It falls back to Modified if there are not enough slots.