Add tree traversal functions. Skip self in Folder/User descendants

This commit is contained in:
ig 2023-03-16 14:13:39 +01:00
parent e3e03fda8b
commit e136767b12
6 changed files with 176 additions and 118 deletions

View File

@ -8,12 +8,14 @@ public static class CredentialsMethods
{
public static Session? Login(this Credentials credentials)
{
if (credentials.Username.IsNullOrEmpty() || credentials.Password.IsNullOrEmpty())
var (username, password) = credentials;
if (username.IsNullOrEmpty() || password.IsNullOrEmpty())
return null;
var user = Db.GetUserByEmail(credentials.Username);
var user = Db.GetUserByEmail(username);
if (user is null || !user.VerifyPassword(credentials.Password))
if (user is null || !user.VerifyPassword(password))
return null;
var session = new Session(user);

View File

@ -21,7 +21,9 @@ public static class FolderMethods
public static IEnumerable<Folder> DescendantFolders(this Folder parent)
{
return parent.Traverse(ChildFolders);
return parent
.TraverseDepthFirstPreOrder(ChildFolders)
.Skip(1); // skip self
}
public static Boolean IsDescendantOf(this Folder folder, Folder ancestor)

View File

@ -73,7 +73,9 @@ public static class UserMethods
public static IEnumerable<User> DescendantUsers(this User parent)
{
return parent.Traverse(ChildUsers);
return parent
.TraverseDepthFirstPreOrder(ChildUsers)
.Skip(1); // skip self
}
public static Boolean IsDescendantOf(this User user, User ancestor)

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@ -1,4 +1,3 @@
using System.Reactive.Linq;
using InnovEnergy.App.Backend.Database;
using Microsoft.OpenApi.Models;
@ -8,7 +7,6 @@ public static class Program
{
public static void Main(String[] args)
{
Db.CreateFakeRelations();
var builder = WebApplication.CreateBuilder(args);

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@ -0,0 +1,147 @@
namespace InnovEnergy.Lib.Utils;
public static class TreeTraversal
{
// public static IEnumerable<T> TraverseDepthFirstPreOrder<T>(this T root, Func<T, IEnumerable<T>> getChildren)
// {
// var stack = new Stack<IEnumerator<T>>();
//
// var iterator = root.AsSingleEnumerator();
//
// while (true)
// {
// while (iterator.MoveNext())
// {
// yield return iterator.Current;
//
// iterator = getChildren(iterator.Current).GetEnumerator();
// stack.Push(iterator);
// }
//
// iterator.Dispose();
// if (stack.Count == 0)
// yield break;
//
// iterator = stack.Pop();
// }
//
// }
public static IEnumerable<T> TraverseDepthFirstPreOrder<T>(this T root, Func<T, IEnumerable<T>> getChildren)
{
return Traverse(root,
getChildren,
branchOpen: true,
branchClose: false,
leaf: true);
}
public static IEnumerable<T> TraverseDepthFirstPostOrder<T>(this T root, Func<T, IEnumerable<T>> getChildren)
{
return Traverse(root,
getChildren,
branchOpen: false,
branchClose: true,
leaf: true);
}
public static IEnumerable<T> TraverseLeaves<T>(this T root, Func<T, IEnumerable<T>> getChildren)
{
return Traverse(root,
getChildren,
branchOpen: false,
branchClose: true,
leaf: false);
}
private static IEnumerable<T> Traverse<T>(T root,
Func<T, IEnumerable<T>> getChildren,
Boolean branchOpen,
Boolean branchClose,
Boolean leaf)
{
// the if-checks on the constant booleans are
// almost free because of modern branch predictors
var stack = new Stack<IEnumerator<T>>();
var it = root.AsSingleEnumerator();
it.MoveNext();
while (true)
{
//////// going down ////////
while (true)
{
var cit = getChildren(it.Current).GetEnumerator();
if (cit.MoveNext()) // node has children, must be a branch
{
if (branchOpen)
yield return it.Current;
stack.Push(it);
it = cit;
}
else // no children, hence a leaf
{
var node = it.Current;
if (leaf)
yield return node;
if (!it.MoveNext())
break; // no more siblings: goto parent
}
}
//////// going up ////////
while (true)
{
it.Dispose();
if (stack.Count == 0) yield break; // we got to the bottom of the stack, were done
it = stack.Pop();
var node = it.Current;
if (branchClose)
yield return node; // we've seen all its children: close the branch
if (it.MoveNext())
break;
}
}
}
public static IEnumerable<T> TraverseBreadthFirst<T>(this T node, Func<T, IEnumerable<T>> getChildren)
{
var queue = new Queue<IEnumerator<T>>();
var iterator = node.AsSingleEnumerator();
while(true)
{
while (iterator.MoveNext())
{
yield return iterator.Current;
iterator.Current
.Apply(getChildren)
.GetEnumerator()
.Apply(queue.Enqueue);
}
iterator.Dispose();
if (queue.Count == 0)
yield break;
iterator = queue.Dequeue();
}
}
}

View File

@ -1,4 +1,5 @@
using System.Diagnostics;
using System.Diagnostics.CodeAnalysis;
using System.Runtime.CompilerServices;
using static System.Runtime.CompilerServices.MethodImplOptions;
@ -6,6 +7,7 @@ namespace InnovEnergy.Lib.Utils;
public static class Utils
{
public static Boolean IsNull<T>([NotNullWhen(returnValue: false)] this T t) => t is null;
public static IEnumerable<String> GetEnumStrings<T>(this T e) where T : Enum
{
@ -20,7 +22,7 @@ public static class Utils
[DebuggerStepThrough][MethodImpl(AggressiveInlining)]
public static T ConvertTo<T>(this IConvertible c) where T : IConvertible
{
var t = typeof (T);
var t = typeof(T);
var type = t.IsEnum
? Enum.GetUnderlyingType(t)
@ -50,13 +52,13 @@ public static class Utils
[DebuggerStepThrough][MethodImpl(AggressiveInlining | AggressiveOptimization)]
public static R Apply<T, R>(this T t, Func<T, R> f) => f(t);
[DebuggerStepThrough]
[MethodImpl(AggressiveInlining | AggressiveOptimization)]
[DebuggerStepThrough][MethodImpl(AggressiveInlining | AggressiveOptimization)]
public static R Apply<T1, T2, R>(this (T1 p1, T2 p2) t, Func<T1, T2, R> f) => f(t.p1, t.p2);
[DebuggerStepThrough]
[MethodImpl(AggressiveInlining | AggressiveOptimization)]
public static R Apply<T1, T2, T3, R>(this (T1 p1, T2 p2, T3 p3) t, Func<T1, T2, T3, R> f) => f(t.p1, t.p2, t.p3);
[DebuggerStepThrough][MethodImpl(AggressiveInlining | AggressiveOptimization)]
public static R Apply<T1, T2, T3, R>(this (T1 p1, T2 p2, T3 p3) t, Func<T1, T2, T3, R> f) => f(t.p1, t.p2, t.p3);
[DebuggerStepThrough][MethodImpl(AggressiveInlining | AggressiveOptimization)]
public static R ApplyOrDefault<T, R>(this T t, Func<T, R> f, R @default)
@ -79,7 +81,7 @@ public static class Utils
? res
: res + length;
}
public static Decimal Modulo(this Decimal dividend, Decimal divisor)
{
var res = dividend % divisor;
@ -89,111 +91,39 @@ public static class Utils
: res + divisor;
}
public static IEnumerable<T> Traverse<T>(this T root, Func<T, IEnumerable<T>> getChildren)
{
var stack = new Stack<IEnumerator<T>>();
var it = root.AsSingleEnumerator();
it.MoveNext();
while (true)
{
//////// going down ////////
while (true)
{
var cit = getChildren(it.Current).GetEnumerator();
if (cit.MoveNext()) // node has children, must be a branch
{
yield return it.Current;
stack.Push(it);
it = cit;
}
else // no children, hence a leaf
{
var node = it.Current;
yield return node;
if (!it.MoveNext())
break; // no more siblings: goto parent
}
}
//////// going up ////////
while (true)
{
it.Dispose();
if (stack.Count == 0)
yield break; // we got to the bottom of the stack, were done
it = stack.Pop();
if (it.MoveNext())
break;
}
}
}
public static Int32 Clamp(this Int32 value, Int32 minValue, Int32 maxValue)
{
var clamped = Math.Min(maxValue, value);
clamped = Math.Max(minValue, clamped);
return clamped;
}
public static Double Clamp(this Double value, Double minValue, Double maxValue)
{
var clamped = Math.Min(maxValue, value);
clamped = Math.Max(minValue, clamped);
return clamped;
}
public static Decimal Clamp(this Decimal value, Decimal minValue, Decimal maxValue)
{
var clamped = Math.Min(maxValue, value);
clamped = Math.Max(minValue, clamped);
return clamped;
}
#pragma warning disable 8714
public static async Task<R> ApplyOrDefault<T, R>(this T t, Func<T, Task<R>> f, R @default)
{
try
{
return await f(t);
}
catch
{
return @default;
}
}
public static R ValueOrDefault<T, R>(this Dictionary<T, R> dict, T key, R defaultValue)
public static R ValueOrDefault<T, R>(this Dictionary<T, R> dict, T key, R defaultValue) where T : notnull
{
return dict.TryGetValue(key, out var value)
? value
: defaultValue;
? value
: defaultValue;
}
public static Dictionary<K, V> CombineDicts<K,V>(params IEnumerable<KeyValuePair<K,V>>[] dicts)
{
return dicts.Flatten().ToDictionary(kv => kv.Key, kv => kv.Value);
}
#pragma warning restore 8714
public static void CopyFilesRecursively(String source, String target)
{
CopyFilesRecursively(new DirectoryInfo(source), new DirectoryInfo(target));
@ -210,27 +140,4 @@ public static class Utils
public static String ExecutingProcessName => Process.GetCurrentProcess().ProcessName;
public static IEnumerable<IEnumerable<T>> TraverseWithPath<T>(this T root, Func<T, IEnumerable<T>> getChildren)
{
var stack = new Stack<IEnumerator<T>>();
stack.Push(root.AsSingleEnumerator());
do
{
for (var top = stack.Peek(); top.MoveNext(); top = Push(top))
yield return stack.Select(p => p.Current);
var popped = stack.Pop();
popped.Dispose();
}
while (stack.Count > 0);
IEnumerator<T> Push(IEnumerator<T> node)
{
var top = getChildren(node.Current).GetEnumerator();
stack.Push(top);
return top;
}
}
}