Acl parser + unit tests

Directory.Packages.props

@@ -19,5 +19,10 @@
     <PackageVersion Include="Npgsql" Version="8.0.5" />
     <PackageVersion Include="Pure.DI" Version="2.1.38" />
     <PackageVersion Include="Xamarin.AndroidX.Core.SplashScreen" Version="1.0.1.1" />
+
+    <PackageVersion Include="coverlet.collector" Version="6.0.2"/>
+    <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="17.11.1"/>
+    <PackageVersion Include="xunit" Version="2.9.2"/>
+    <PackageVersion Include="xunit.runner.visualstudio" Version="2.8.2"/>
   </ItemGroup>
 </Project>

pgLabII.PgUtils.Tests/Acls/AclParserTests.cs

@@ -0,0 +1,17 @@
+namespace pgLabII.PgUtils.Tests;
+
+public class AclParserTests
+{
+    [Theory]
+    [InlineData("foo=rw/postgres", "foo", "rw", "postgres")]
+    [InlineData("\"Test\"\"=\"=rw/postgres", "Test\"=", "rw", "postgres")]
+    [InlineData("foo=rw/\"Test\"\"=\"", "foo", "rw", "Test\"=")]
+    public void Test1(string aclString, string expectedGrantee, string expectedRights, string expectedGrantor)
+    {
+        AclParser parser = new();
+        Acl acl = parser.Parse(aclString);
+        Assert.Equal(expectedGrantee, acl.Grantee);
+        Assert.Equal(expectedRights, acl.Rights);
+        Assert.Equal(expectedGrantor, acl.Grantor);
+    }
+}

pgLabII.PgUtils.Tests/pgLabII.PgUtils.Tests.csproj

@@ -0,0 +1,25 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+    <PropertyGroup>
+        <TargetFramework>net9.0</TargetFramework>
+        <ImplicitUsings>enable</ImplicitUsings>
+        <Nullable>enable</Nullable>
+        <IsPackable>false</IsPackable>
+    </PropertyGroup>
+
+    <ItemGroup>
+        <PackageReference Include="coverlet.collector" />
+        <PackageReference Include="Microsoft.NET.Test.Sdk" />
+        <PackageReference Include="xunit" />
+        <PackageReference Include="xunit.runner.visualstudio" />
+    </ItemGroup>
+
+    <ItemGroup>
+        <Using Include="Xunit" />
+    </ItemGroup>
+
+    <ItemGroup>
+      <ProjectReference Include="..\pgLabII.PgUtils\pgLabII.PgUtils.csproj" />
+    </ItemGroup>
+
+</Project>

pgLabII.PgUtils/Acls/AclParser.cs

@@ -0,0 +1,113 @@
+using System.Text;
+
+namespace pgLabII.PgUtils;
+
+public class Acl(string grantee, string rights, string grantor)
+{
+    public string Grantee { get; } = grantee;
+    public string Rights { get; } = rights;
+    public string Grantor { get; } = grantor;
+}
+/// <summary>
+/// Parser for acl's. Acl's have a fairly simple structure grantee=right/grantor see also https://www.postgresql.org/docs/current/ddl-priv.html
+/// When the grantee is empty it is "PUBLIC" which you can see as a wildcard that matches everybody that can authenticate.
+/// Because the grantee and grantor name can contain special characters there is an escape mechinism in place.
+/// When the name contains a conflicting character it is quoted. If the name contains a quote it is doubles. 
+/// </summary>
+public class AclParser
+{
+    private int _position = 0;
+    private string _input = null!;
+    
+    public Acl Parse(string acl)
+    {
+        _input = acl;
+        _position = 0;
+        ConsumeWhitespace();
+        string grantee = ConsumeRoleName();
+        string rights = ConsumeRights();
+        if (Current() != '/')
+            throw new ArgumentException("Unexpected symbol in acl string");
+        _position++;
+        string grantor = ConsumeRoleName();
+        return new Acl(grantee, rights, grantor);
+    }
+
+    /// <summary>
+    /// There is a limited set of possible characters for the rights
+    /// </summary>
+    /// <returns></returns>
+    /// <exception cref="NotImplementedException"></exception>
+    private string ConsumeRights()
+    {
+        if (Current() != '=')
+            throw new ArgumentException("Unexpected symbol in acl string");
+        _position++;
+        int start = _position;
+        while (NotAtEnd() && Current() != '/')
+            _position++;
+        
+        return _input.Substring(start, _position - start);
+    }
+
+    // Whitespace should have been consumed
+    // There should be either a " in which case the name is quoted
+    // a = in which case there is no name ie PUBLIC
+    // all other cases it is an unquoted name
+    private string ConsumeRoleName() =>
+        _input[_position] switch
+        {
+            '=' => "",
+            '"' => ParseQuotedName(),
+            _ => ParseUnquotedName()
+        };
+
+    private string ParseQuotedName()
+    {
+        _position++; // consume opening quote
+        int start = _position;
+        StringBuilder sb = new();
+
+        while (true)
+        {
+            while (NotAtEnd() && Current() != '"')
+                _position++;
+
+            char peek = _position + 1 < _input.Length ? _input[_position + 1] : '\0';  
+            if (peek == '"')
+            {
+                _position++;
+                sb.Append(_input.AsSpan(start, _position - start));
+                _position++;
+                start = _position;
+            }
+            else
+            {
+                sb.Append(_input.AsSpan(start, _position - start));
+                _position++;
+                break;
+            }
+        }
+
+        return sb.ToString();
+    }
+
+    private string ParseUnquotedName()
+    {
+        int start = _position;
+        while (NotAtEnd() && Current() != '=')
+            _position++;
+        
+        return _input.Substring(start, _position - start);
+    }
+
+    private void ConsumeWhitespace()
+    {
+        while (NotAtEnd() && char.IsWhiteSpace(Current()))
+            ++_position;
+    }
+    
+    private bool NotAtEnd() => _position < _input.Length;
+    
+    private char Current() => _input[_position];
+}

pgLabII.PgUtils/pgLabII.PgUtils.csproj

@@ -0,0 +1,9 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+    <PropertyGroup>
+        <TargetFramework>net9.0</TargetFramework>
+        <ImplicitUsings>enable</ImplicitUsings>
+        <Nullable>enable</Nullable>
+    </PropertyGroup>
+
+</Project>

pgLabII.sln

@@ -18,6 +18,10 @@ Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Solution Items", "Solution
 EndProject
 Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "UI", "UI", "{EBBC2081-5061-4843-B420-AB4C48A5C283}"
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "pgLabII.PgUtils", "pgLabII.PgUtils\pgLabII.PgUtils.csproj", "{6694EE99-3AEA-4823-B2C3-02F28F575D14}"
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "pgLabII.PgUtils.Tests", "pgLabII.PgUtils.Tests\pgLabII.PgUtils.Tests.csproj", "{915C5439-4CF5-4625-AB7B-24F0E34E5B5F}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -41,6 +45,14 @@ Global
 		{7AD1DAC8-7FBE-49D5-8614-7321233DB82E}.Debug|Any CPU.Deploy.0 = Debug|Any CPU
 		{7AD1DAC8-7FBE-49D5-8614-7321233DB82E}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{7AD1DAC8-7FBE-49D5-8614-7321233DB82E}.Release|Any CPU.Build.0 = Release|Any CPU
+		{6694EE99-3AEA-4823-B2C3-02F28F575D14}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{6694EE99-3AEA-4823-B2C3-02F28F575D14}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{6694EE99-3AEA-4823-B2C3-02F28F575D14}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{6694EE99-3AEA-4823-B2C3-02F28F575D14}.Release|Any CPU.Build.0 = Release|Any CPU
+		{915C5439-4CF5-4625-AB7B-24F0E34E5B5F}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{915C5439-4CF5-4625-AB7B-24F0E34E5B5F}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{915C5439-4CF5-4625-AB7B-24F0E34E5B5F}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{915C5439-4CF5-4625-AB7B-24F0E34E5B5F}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE