SccGet function

Članak
01/12/2024

This function retrieves a copy of one or more files for viewing and compiling but not for editing. In most systems, the files are tagged as read-only.

Syntax

SCCRTN SccGet(
   LPVOID    pvContext,
   HWND      hWnd,
   LONG      nFiles,
   LPCSTR*   lpFileNames,
   LONG      fOptions,
   LPCMDOPTS pvOptions
);

Parameters

pvContext

[in] The context structure of the source control plug-in.

hWnd

[in] A handle to the IDE window that the source control plug-in can use as a parent for any dialog boxes that it provides.

nFiles

[in] Number of files specified in the lpFileNames array.

lpFileNames

[in] Array of fully qualified names of files to be retrieved.

fOptions

[in] Command flags (SCC_GET_ALL, SCC_GET_RECURSIVE).

pvOptions

[in] Source control plug-in-specific options.

Return value

The source control plug-in implementation of this function is expected to return one of the following values:

Value	Description
SCC_OK	Success of get operation.
SCC_E_FILENOTCONTROLLED	The file is not under source control.
SCC_E_OPNOTSUPPORTED	The source control system does not support this operation.
SCC_E_FILEISCHECKEDOUT	Cannot get the file that the user currently has checked out.
SCC_E_ACCESSFAILURE	There was a problem accessing the source control system, probably due to network or contention issues. A retry is recommended.
SCC_E_NOSPECIFIEDVERSION	Specified an invalid version or date/time.
SCC_E_NONSPECIFICERROR	Nonspecific failure; file was not synchronized.
SCC_I_OPERATIONCANCELED	Operation cancelled before completion.
SCC_E_NOTAUTHORIZED	The user is not authorized to perform this operation.

Remarks

This function is called with a count and an array of names of the files to be retrieved. If the IDE passes the flag SCC_GET_ALL, this means that the items in lpFileNames are not files but directories, and that all files under source control in the given directories are to be retrieved.

The SCC_GET_ALL flag can be combined with the SCC_GET_RECURSIVE flag to retrieve all files in the given directories and all subdirectories as well.

Note

SCC_GET_RECURSIVE should never be passed without SCC_GET_ALL. Also, note that if directories C:\A and C:\A\B are both passed on a recursive get, C:\A\B and all its subdirectories will actually be retrieved twice. It is the IDE's responsibility—and not the source control plug-in's—to make sure that duplicates such as this are kept out of the array.

Finally, even if a source control plug-in specified the SCC_CAP_GET_NOUI flag on initialization, indicating that it does not have a user interface for a Get command, this function may still be called by the IDE to retrieve files. The flag simply means that the IDE does not display a Get menu item and that the plug-in is not expected to provide any UI.

Rename files and SccGet

Situation: a user checks out a file, for example, a.txt, and modifies it. Before a.txt can be checked in, a second user renames a.txt to b.txt in the source control database, checks out b.txt, makes some modifications to the file, and checks the file in. The first user wants the changes made by the second user so the first user renames their local version of a.txt file to b.txt and does a get on the file. However, the local cache that keeps track of version numbers still thinks the first version of a.txt is stored locally and so source control cannot resolve the differences.

There are two ways to resolve this situation where the local cache of source control versions becomes out of sync with the source control database:

Do not allow renaming a file in the source control database that is currently checked out.
Do the equivalent of "delete old" followed by "add new". The following algorithm is one way to accomplish this.
1. Call the SccQueryChanges function to learn about the renaming of a.txt to b.txt in the source control database.
2. Rename the local a.txt to b.txt.
3. Call the SccGet function for both a.txt and b.txt.
4. Because a.txt does not exist in the source control database, the local version cache is purged of the missing a.txt version information.
5. The b.txt file being checked out is merged with the contents of the local b.txt file.
6. The updated b.txt file can now be checked in.

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