adding support for absolute paths, updating readme files

README.md

@@ -78,6 +78,7 @@ The above command will automatically fail the build if the average code coverage
 
 ### Excluding From Coverage
 
+#### Attributes  
 You can ignore a method or an entire class from code coverage by creating and applying any of the following attributes:
 
 * ExcludeFromCoverage
@@ -85,6 +86,16 @@ You can ignore a method or an entire class from code coverage by creating and ap
 
 Coverlet just uses the type name, so the attributes can be created under any namespace of your choosing.
 
+#### File Path  
+You can also ignore code coverage by specifing files using the `Exclude` property
+ - Use single or multiple paths (separate by comma)
+ - Use absolute or relative paths (relative to the project directory)
+ - Use file path or directory path with globbing (e.g `dir1/*.cs`)
+
+```bash
+dotnet test /p:CollectCoverage=true /p:Exclude=\"../dir1/class1.cs,../dir2/*.cs,../dir3/**/*.cs,\"
+```
+
 ## Roadmap
 
 * Filter modules to be instrumented

build.proj

@@ -28,7 +28,7 @@
   </Target>
   
   <Target Name="RunTestsWithExclude" AfterTargets="RunTests">
-    <Exec Command="dotnet test --no-build $(MSBuildThisFileDirectory)test\coverlet.core.tests\coverlet.core.tests.csproj -c $(Configuration) /p:CollectCoverage=true /p:CoverletOutputFormat=opencover /p:Exclude=\&quot;../../src/coverlet.core/Instrumentation/**/*.cs,../../src/coverlet.core/Reporters/**/*.cs\&quot;"/>
+    <Exec Command="dotnet test --no-build $(MSBuildThisFileDirectory)test\coverlet.core.tests\coverlet.core.tests.csproj -c $(Configuration) /p:CollectCoverage=true /p:CoverletOutputFormat=opencover /p:Exclude=\&quot;../../src/coverlet.core/Instrumentation/**/*.cs,$(MSBuildThisFileDirectory)/src/coverlet.core/Reporters/**/*.cs\&quot;"/>
   </Target>
 
   <Target Name="CreateNuGetPackage" AfterTargets="RunTestsWithExclude" Condition="$(Configuration) == 'Release'">

src/coverlet.core/Helpers/InstrumentationHelper.cs

@@ -113,19 +113,39 @@ namespace Coverlet.Core.Helpers
         public static IEnumerable<string> GetExcludedFiles(IEnumerable<string> excludeRules, 
                                                            string parentDir = null) 
         {
+            const string RELATIVE_KEY = nameof(RELATIVE_KEY);
             parentDir = string.IsNullOrWhiteSpace(parentDir)? Directory.GetCurrentDirectory() : parentDir;
+            
             if (excludeRules == null || !excludeRules.Any()) return Enumerable.Empty<string>();
-            var matcher = new Matcher();
+            
+            var matcherDict = new Dictionary<string, Matcher>(){ {RELATIVE_KEY, new Matcher()}};
             foreach (var excludeRule in excludeRules)
             {
-                matcher.AddInclude(excludeRule);
+                if (Path.IsPathRooted(excludeRule)) {
+                    var root = Path.GetPathRoot(excludeRule);
+                    if (!matcherDict.ContainsKey(root)) {
+                        matcherDict.Add(root, new Matcher());
+                    } 
+                    matcherDict[root].AddInclude(excludeRule.Substring(root.Length));
+                } else {
+                    matcherDict[RELATIVE_KEY].AddInclude(excludeRule);
+                }
+                
             }
-        
-            DirectoryInfo directoryInfo = new DirectoryInfo(parentDir);
             
-            var fileMatchResult = matcher.Execute(new DirectoryInfoWrapper(directoryInfo));
-            return fileMatchResult.Files
-                .Select(f => Path.GetFullPath(Path.Combine(directoryInfo.ToString(), f.Path)));
+            var files = new List<string>();
+            foreach(var entry in matcherDict)
+            {
+                var root = entry.Key;
+                var matcher = entry.Value;
+                var directoryInfo = new DirectoryInfo(root.Equals(RELATIVE_KEY) ? parentDir : root);
+                var fileMatchResult = matcher.Execute(new DirectoryInfoWrapper(directoryInfo));
+                var currentFiles = fileMatchResult.Files
+                    .Select(f => Path.GetFullPath(Path.Combine(directoryInfo.ToString(), f.Path)));
+                files.AddRange(currentFiles);
+            }
+            
+            return files.Distinct();
         }
     }
 }