/// <summary>
/// Saves the metadata for a branch that is part of this store.
/// </summary>
/// <param name="folderName">The path for the folder that holds branch data.</param>
/// <param name="ac">The branch metadata to be saved.</param>
internal static void SaveBranchInfo(string folderName, BranchInfo ac)
{
Directory.CreateDirectory(folderName);
string data = JsonConvert.SerializeObject(ac, Formatting.Indented);
string fileName = Path.Combine(folderName, ac.BranchId + ".ac");
File.WriteAllText(fileName, data);
}
/// <summary>
/// Creates a new instance of <see cref="Branch"/> (but does
/// not load it).
/// </summary>
/// <param name="store">The command store that this branch is part of (not null)</param>
/// <param name="ac">Metadata relating to the branch (not null)</param>
/// <exception cref="ArgumentNullException">
/// The supplied command store or metadata is undefined</exception>
internal Branch(CmdStore store, BranchInfo ac)
{
Store = store ?? throw new ArgumentNullException(nameof(store));
Info = ac ?? throw new ArgumentNullException(nameof(ac));
Commands = new List <CmdData>();
Parent = null;
Children = new List <Branch>();
}
/// <summary>
/// Accepts data from another command store.
/// </summary>
/// <param name="source">A name that identifies the command store that is
/// the source of the data.</param>
/// <param name="ac">The metadata for the branch the commands are part of.</param>
/// <param name="data">The command data to be appended to the remote branch.</param>
void IRemoteStore.Push(string source, BranchInfo ac, CmdData[] data)
{
// Clone the supplied metadata (if the call actually comes from
// the current application, we don't want to mutate the metadata)
BranchInfo acCopy = ac.CreateCopy();
string altName = acCopy.BranchName == "+" ? source : null;
CopyIn(acCopy, data, altName);
}
/// <summary>
/// Performs the data processing associated with a command.
/// </summary>
public void Process(ExecutionContext context)
{
CmdStore cs = context?.Store ?? throw new ApplicationException("Undefined store");
uint numCmd = (Input as ICreateBranch).CommandCount;
if (numCmd == 0)
{
throw new ApplicationException(nameof(numCmd));
}
// Confirm that the name for the new branch is not a
// duplicate (considering just the children of the
// current branch)
string name = (Input as ICreateBranch).Name;
Branch parent = cs.Current;
Branch oldBranch = parent.GetChild(name);
if (oldBranch != null)
{
throw new ArgumentException(
$"Branch {name} previously created at {oldBranch.Info.CreatedAt}");
}
// Confirm that the new branch name is acceptable to the command store
if (!cs.IsValidBranchName(name))
{
throw new ArgumentException($"Branch name '{name}' is not allowed");
}
var ac = new BranchInfo(
storeId: cs.Id,
parentId: parent.Id,
branchId: Guid.NewGuid(),
branchName: name,
createdAt: Input.CreatedAt,
updatedAt: Input.CreatedAt,
commandDiscount: 1,
refreshCount: numCmd);
// Update internal structure to include the new branch
var newBranch = new Branch(cs, ac)
{
Parent = parent
};
parent.Children.Add(newBranch);
cs.Branches.Add(ac.BranchId, newBranch);
// Save the metadata for the new branch
cs.SaveBranchInfo(newBranch);
// And save the CreateBranch command itself
newBranch.SaveData(Input);
}
/// <summary>
/// Initializes a new instance of the <see cref="MemoryStore"/> class.
/// </summary>
/// <param name="rootAc">Metadata for the root branch</param>
MemoryStore(BranchInfo rootAc)
: base(String.Empty,
new StoreInfo(rootAc),
new BranchInfo[] { rootAc },
rootAc.BranchId)
{
AcFiles = new Dictionary <Guid, string>();
Data = new Dictionary <string, string>();
SaveBranchInfo(rootAc);
}
/// <summary>
/// Prepares an instance of <see cref="CmdData"/> for
/// the next command that will be appended to the
/// current branch.
/// </summary>
/// <param name="commandName">A name that identifies
/// the command type (a class name is one of potentially
/// many choices)</param>
/// <returns>An instance of command data that can
/// be appended to the current branch.</returns>
/// <remarks>
/// The caller will usually append additional properties
/// that are specific to the command.
/// </remarks>
public CmdData CreateCmdData(string commandName)
{
BranchInfo ac = Store.Current.Info;
// Never return command data for a completed branch
if (ac.IsCompleted)
{
throw new InvalidOperationException("Branch has already been completed");
}
// And never for a remote
// May be doing a push (which you can do from any branch)
//if (Store.Current.IsRemote)
// throw new InvalidOperationException("Unexpected attempt to append to a remote branch");
return(new CmdData(
cmdName: commandName,
sequence: ac.CommandCount,
createdAt: DateTime.UtcNow));
}
void SaveBranchInfo(BranchInfo ac)
{
string data = JsonConvert.SerializeObject(ac, Formatting.Indented);
string sql;
int nRows = 0;
if (ac.CommandCount == 0)
{
Database.ExecuteTransaction(() =>
{
// Create the data table for the new branch
sql = $"CREATE TABLE [{ac.BranchId}] " +
"(Sequence INTEGER NOT NULL PRIMARY KEY" +
",Data JSON NOT NULL)";
Database.ExecuteNonQuery(sql);
// Create a view with a matching name (this is not needed by the
// software, but may make it easier to debug things)
string viewName = GetDataViewName(ac.BranchName);
sql = $"CREATE VIEW [{viewName}] AS SELECT * FROM [{ac.BranchId}]";
Database.ExecuteNonQuery(sql);
// Record branch metadata
sql = $"INSERT INTO Branches (Id,Name,CreatedAt,Data) VALUES " +
$"('{ac.BranchId}', '{viewName}', '{ac.CreatedAt:o}', '{data}')";
nRows = Database.ExecuteNonQuery(sql);
});
}
else
{
sql = $"UPDATE Branches SET Data='{data}' WHERE Id='{ac.BranchId}'";
nRows = Database.ExecuteNonQuery(sql);
}
if (nRows != 1)
{
throw new ApplicationException($"Update for branch changed {nRows} row`s".TrimExtras());
}
}
internal static MemoryStore Create(CmdData args)
{
// Disallow an attempt to clone another memory store
// TODO: How should the ICloneStore input reference another memory store?
if (args.CmdName == nameof(ICloneStore))
{
throw new NotImplementedException(nameof(MemoryStore));
}
// Create the AC file that represents the store root branch
Guid storeId = args.GetGuid(nameof(ICreateStore.StoreId));
string name = args.GetValue <string>(nameof(ICreateStore.Name));
var ac = new BranchInfo(storeId: storeId,
parentId: Guid.Empty,
branchId: storeId,
branchName: name,
createdAt: args.CreatedAt);
return(new MemoryStore(ac));
}
public void Process(ExecutionContext context)
{
CmdStore cs = context.Store;
StoreInfo storeInfo = cs.Store;
string upLoc = storeInfo.UpstreamLocation;
if (String.IsNullOrEmpty(upLoc))
{
throw new ApplicationException("There is no upstream location");
}
// Collate how much we already have in all remote branches.
// We may have previously pushed some local branches to the remote
// store, but nothing is supposed to mutate those remote copies.
IdCount[] have = cs.Branches.Values
.Where(x => x.IsRemote)
.Select(x => new IdCount(x.Id, x.Info.CommandCount))
.ToArray();
// Open a channel to the upstream store
IRemoteStore rs = context.GetRemoteStore(upLoc);
// Determine what we are missing (including any new branches in the remote)
IdRange[] toFetch = rs.GetMissingRanges(cs.Id, have, true);
// How many commands do we need to fetch
uint total = (uint)toFetch.Sum(x => x.Size);
Log.Info($"To fetch {total} command`s from {toFetch.Length} branch`es".TrimExtras());
// Retrieve the command data from the remote, keeping new branches
// apart from appends to existing branches.
var newBranchData = new Dictionary <BranchInfo, CmdData[]>();
var moreBranchData = new Dictionary <BranchInfo, CmdData[]>();
foreach (IdRange idr in toFetch)
{
// Fetch the remote AC file
BranchInfo ac = rs.GetBranchInfo(idr.Id);
if (ac == null)
{
throw new ApplicationException("Could not locate remote branch " + idr.Id);
}
// And the relevant data
Log.Info($"Fetch [{idr.Min},{idr.Max}] for {ac.BranchName} ({ac.BranchId})");
CmdData[] branchData = rs.GetData(idr).ToArray();
if (cs.FindBranch(ac.BranchId) == null)
{
newBranchData.Add(ac, branchData);
}
else
{
moreBranchData.Add(ac, branchData);
}
}
// All done with the remote store
// Copy any brand new branches (ensuring they get created in the
// right order so that parent/child relationships can be formed
// as we go).
foreach (KeyValuePair <BranchInfo, CmdData[]> kvp in newBranchData.OrderBy(x => x.Key.CreatedAt))
{
cs.CopyIn(kvp.Key, kvp.Value);
}
// Append command data for branches we previously had (the order
// shouldn't matter)
foreach (KeyValuePair <BranchInfo, CmdData[]> kvp in moreBranchData)
{
cs.CopyIn(kvp.Key, kvp.Value);
}
Log.Info("Fetch completed");
// Reload the current command stream (from scratch, kind of brute force,
// not sure whether appending the new commands would really be sufficient)
// TODO: Is this really necessary? Perhaps only if the current branch has
// been fetched (the stuff we're fetching should only come from remotes,
// but the current branch could be one of those remotes)
//cs.Stream = new CmdStream(cs.Current);
}
internal static FileStore Create(CmdData args)
{
// Expand the supplied name to include the current working directory (or
// expand a relative path)
string enteredName = args.GetValue <string>(nameof(ICreateStore.Name));
string name = Path.GetFileNameWithoutExtension(enteredName);
string folderName = Path.GetFullPath(enteredName);
// Disallow if the folder name already exists.
// It may be worth relaxing this rule at some future date. The
// reason for disallowing it is because an existing folder may
// well contain sub-folders, but we also use sub-folders to
// represent the branch hierarchy. So things would be a bit
// mixed up. That said, it would be perfectly plausible to
// place branch sub-folders under a separate ".ac" folder (in
// much the same way as git). That might be worth considering
// if we want to support a "working directory" like that
// provided by git.
if (Directory.Exists(folderName))
{
throw new ApplicationException($"{folderName} already exists");
}
// Confirm the folder is on a local drive
if (!IsLocalDrive(folderName))
{
throw new ApplicationException("Command stores can only be initialized on a local fixed drive");
}
// Create the folder for the store (but if the folder already exists,
// confirm that it does not already hold any AC files).
if (Directory.Exists(folderName))
{
if (GetAcFilePath(folderName) != null)
{
throw new ApplicationException($"{folderName} has already been initialized");
}
}
else
{
Log.Info("Creating " + folderName);
Directory.CreateDirectory(folderName);
}
Guid storeId = args.GetGuid(nameof(ICreateStore.StoreId));
FileStore result = null;
// If we're cloning, copy over the source data
if (args.CmdName == nameof(ICloneStore))
{
// TODO: When cloning from a real remote, using wget might be a
// good choice (but that doesn't really fit with what's below)
ICloneStore cs = (args as ICloneStore);
IRemoteStore rs = GetRemoteStore(cs);
// Retrieve metadata for all remote branches
BranchInfo[] acs = rs.GetBranches()
.OrderBy(x => x.CreatedAt)
.ToArray();
var branchFolders = new Dictionary <Guid, string>();
// Copy over all branches
foreach (BranchInfo ac in acs)
{
// Get the data for the branch (do this before we do any tweaking
// of the folder path from the AC file -- if the command supplier is
// a local file store, we won't be able to read the command data files
// after changing the folder name recorded in the AC)
IdRange range = new IdRange(ac.BranchId, 0, ac.CommandCount - 1);
CmdData[] data = rs.GetData(range).ToArray();
// TODO: what follows is very similar to the CopyIn method.
// Consider using that instead (means an empty FileStore needs
// to be created up front)
// Determine the output location for the AC file (relative to the
// location that should have already been defined for the parent)
if (!branchFolders.TryGetValue(ac.ParentId, out string parentFolder))
{
Debug.Assert(ac.ParentId.Equals(Guid.Empty));
parentFolder = folderName;
}
string dataFolder = Path.Combine(parentFolder, ac.BranchName);
branchFolders[ac.BranchId] = dataFolder;
SaveBranchInfo(dataFolder, ac);
// Copy over the command data
foreach (CmdData cd in data)
{
FileStore.WriteData(dataFolder, cd);
}
}
// If the origin is a folder on the local file system, ensure it's
// saved as an absolute path (relative specs may confuse directory
// navigation, depending on what the current directory is at the time)
string origin = cs.Origin;
if (Directory.Exists(origin))
{
origin = Path.GetFullPath(origin);
}
// Save the store metadata
var root = new StoreInfo(storeId, name, rs.Id, origin);
SaveStoreInfo(folderName, root);
// And suck it back up again
string acSpec = Path.Combine(folderName, acs[0].BranchId + ".ac");
result = FileStore.Load(acSpec);
}
else
{
// Create the AC file that represents the store root branch
var ac = new BranchInfo(storeId: storeId,
parentId: Guid.Empty,
branchId: storeId,
branchName: name,
createdAt: args.CreatedAt);
// Create the store metadata
var storeInfo = new StoreInfo(storeId, name, Guid.Empty);
// Create the store and save it
result = new FileStore(folderName,
storeInfo,
new BranchInfo[] { ac },
ac.BranchId);
// Save the AC file plus the store metadata
FileStore.SaveBranchInfo(folderName, ac);
result.SaveStoreInfo();
}
return(result);
}
/// <summary>
/// Copies in data from a remote branch.
/// </summary>
/// <param name="ac">The branch metadata received from a remote store
/// (this will be used to replace any metadata already held locally).</param>
/// <param name="data">The command data to append to the local branch.</param>
/// <param name="altName">An alternative name to assign to the branch.</param>
/// <exception cref="ApplicationException">
/// Attempt to import remote data into a local branch</exception>
public override void CopyIn(BranchInfo ac, CmdData[] data, string altName = null)
{
// The incoming data can only come from a remote store
Debug.Assert(!ac.StoreId.Equals(this.Id));
// Define the local location for the AC file (relative to the
// location that should have already been defined for the parent).
// There could be no parent if we're copying in command data from
// the root branch.
string dataFolder;
Branch parent;
if (ac.ParentId.Equals(Guid.Empty))
{
parent = null;
dataFolder = RootDirectoryName;
}
else
{
parent = FindBranch(ac.ParentId);
if (parent == null)
{
throw new ApplicationException("Cannot find parent branch " + ac.ParentId);
}
string parentDir = GetBranchDirectoryName(parent);
dataFolder = Path.Combine(parentDir, altName ?? ac.BranchName);
}
// Save the supplied AC in its new location (if the branch already
// exists locally, this will overwrite the AC)
SaveBranchInfo(dataFolder, ac);
Branch branch = FindBranch(ac.BranchId);
if (branch == null)
{
Log.Trace($"Copying {data.Length} commands to {dataFolder}");
Debug.Assert(data[0].Sequence == 0);
Debug.Assert(data[0].CmdName == nameof(ICreateBranch));
Debug.Assert(parent != null);
// Create the new branch
branch = new Branch(this, ac)
{
Parent = parent
};
parent.Children.Add(branch);
Branches.Add(ac.BranchId, branch);
}
else
{
Log.Trace($"Appending {data.Length} commands to {dataFolder}");
if (!branch.IsRemote)
{
throw new ApplicationException("Attempt to import remote data into a local branch");
}
// Replace the cached metadata
branch.Info = ac;
}
// Copy over the command data
foreach (CmdData cd in data)
{
WriteData(dataFolder, cd);
}
}
internal static SQLiteStore Create(CmdData args)
{
// Disallow store names that correspond to tables in the database (bear
// in mind that the entered name may or may not include a directory path)
string enteredName = args.GetValue <string>(nameof(ICreateStore.Name));
string name = Path.GetFileNameWithoutExtension(enteredName);
if (IsReservedName(name))
{
throw new ApplicationException("Store name not allowed");
}
// Expand the supplied name to include the current working directory (or
// expand a relative path)
string fullSpec = Path.GetFullPath(enteredName);
string fileType = Path.GetExtension(fullSpec);
if (String.IsNullOrEmpty(fileType))
{
fullSpec += ".ac-sqlite";
}
// Disallow if the database file already exists
if (File.Exists(fullSpec))
{
throw new ApplicationException($"{fullSpec} already exists");
}
// Confirm the file is on a local drive
if (!IsLocalDrive(fullSpec))
{
throw new ApplicationException("Command stores can only be initialized on a local fixed drive");
}
// Ensure the folder exists
string folderName = Path.GetDirectoryName(fullSpec);
if (!Directory.Exists(folderName))
{
Log.Trace("Creating " + folderName);
Directory.CreateDirectory(folderName);
}
Guid storeId = args.GetGuid(nameof(ICreateStore.StoreId));
SQLiteStore result = null;
if (args.CmdName == nameof(ICloneStore))
{
// Copy the SQLite database
// TODO: To handle database files on remote machines
ICloneStore cs = (args as ICloneStore);
Log.Info($"Copying {cs.Origin} to {fullSpec}");
File.Copy(cs.Origin, fullSpec);
// Load the copied store
result = SQLiteStore.Load(fullSpec, cs);
}
else
{
Log.Info("Creating " + fullSpec);
SQLiteDatabase db = CreateDatabase(fullSpec);
// Create the AC file that represents the store root branch
var ac = new BranchInfo(storeId: storeId,
parentId: Guid.Empty,
branchId: storeId,
branchName: name,
createdAt: args.CreatedAt);
// Create the store metadata
var storeInfo = new StoreInfo(storeId, name, Guid.Empty);
// Create the store and save it
result = new SQLiteStore(storeInfo,
new BranchInfo[] { ac },
ac.BranchId,
db);
// Save the info for the master branch plus the store metadata
result.SaveBranchInfo(ac);
result.SaveStoreInfo();
// The last branch is the root of the new database
result.SaveProperty(PropertyNaming.LastBranch, storeId.ToString());
}
return(result);
}
/// <summary>
/// Saves the metadata for a branch that is part of this store.
/// </summary>
/// <param name="ac">The branch metadata to be saved.</param>
void SaveBranchInfo(BranchInfo ac)
{
string data = JsonConvert.SerializeObject(ac, Formatting.Indented);
AcFiles[ac.BranchId] = data;
}
/// <summary>
/// Copies in data from a new remote branch.
/// </summary>
/// <param name="ac">The branch metadata received from a remote store.</param>
/// <param name="data">The command data for the branch</param>
/// <param name="altName">An alternative name to assign to the branch.</param>
public virtual void CopyIn(BranchInfo ac, CmdData[] data, string altName = null)
{
// Currently implemented only by FileStore
throw new NotImplementedException();
}
/// <summary>
/// Creates a new instance of <see cref="StoreInfo"/> for
/// a brand new command store.
/// </summary>
/// <param name="ac">The branch metadata for the root branch</param>
internal StoreInfo(BranchInfo ac)
: this(ac.StoreId, ac.BranchName, Guid.Empty)
{
}