Enhance error handling when native methods return 0 or positive values as success signals

nulltoken · nulltoken · commit 381521c83e1c · 2011-06-01T21:28:54.000+02:00
Usually libgit2 API returns negative values for errors and 0 (zero) when the methods executed successfully. In some rare cases, some native methods may additionally return positive values. This fix cope with this.
diff --git a/LibGit2Sharp/Core/Ensure.cs b/LibGit2Sharp/Core/Ensure.cs
@@ -38,11 +38,24 @@ public static void ArgumentNotNullOrEmptyString(string argumentValue, string arg
 
         /// <summary>
         ///   Check that the result of a C call was successful
+        /// <para>
+        /// This usually means that the method is expected to return 0.
+        /// In some rare cases, some methods may return negative values for errors and
+        /// positive values carrying information. Those positive values should be interpreted
+        /// as successful calls as well.
+        /// </para>
         /// </summary>
-        /// <param name = "result">The result.</param>
-        public static void Success(int result)
+        /// <param name = "result">The result to examine.</param>
+        /// <param name="allowPositiveResult">False to only allow success when comparing against 0, 
+        /// True when positive values are allowed as well.</param>
+        public static void Success(int result, bool allowPositiveResult = false)
         {
-            if (result == (int) GitErrorCode.GIT_SUCCESS)
+            if (result == (int)GitErrorCode.GIT_SUCCESS)
+            {
+                return;
+            }
+
+            if (allowPositiveResult && result > (int)GitErrorCode.GIT_SUCCESS)
             {
                 return;
             }
@@ -65,7 +78,7 @@ public static void ArgumentConformsTo<T>(T argumentValue, Func<T, bool> checker,
             {
                 return;
             }
-            
+
             throw new ArgumentException(argumentName);
         }
     }
diff --git a/LibGit2Sharp/Index.cs b/LibGit2Sharp/Index.cs
@@ -30,7 +30,10 @@ public IndexEntry this[string path]
             {
                 Ensure.ArgumentNotNullOrEmptyString(path, "path");
 
-                return this[NativeMethods.git_index_find(handle, path)];
+                int res = NativeMethods.git_index_find(handle, path);
+                Ensure.Success(res, true);
+
+                return this[res];
             }
         }
 

Original file line number	Diff line number	Diff line change
`@@ -38,11 +38,24 @@ public static void ArgumentNotNullOrEmptyString(string argumentValue, string arg`
`38`	`38`
`39`	`39`	`/// <summary>`
`40`	`40`	`/// Check that the result of a C call was successful`
	`41`	`+ /// <para>`
	`42`	`+ /// This usually means that the method is expected to return 0.`
	`43`	`+ /// In some rare cases, some methods may return negative values for errors and`
	`44`	`+ /// positive values carrying information. Those positive values should be interpreted`
	`45`	`+ /// as successful calls as well.`
	`46`	`+ /// </para>`
`41`	`47`	`/// </summary>`
`42`		`- /// <param name = "result">The result.</param>`
`43`		`- public static void Success(int result)`
	`48`	`+ /// <param name = "result">The result to examine.</param>`
	`49`	`+ /// <param name="allowPositiveResult">False to only allow success when comparing against 0,`
	`50`	`+ /// True when positive values are allowed as well.</param>`
	`51`	`+ public static void Success(int result, bool allowPositiveResult = false)`
`44`	`52`	`{`
`45`		`- if (result == (int) GitErrorCode.GIT_SUCCESS)`
	`53`	`+ if (result == (int)GitErrorCode.GIT_SUCCESS)`
	`54`	`+ {`
	`55`	`+ return;`
	`56`	`+ }`
	`57`	`+`
	`58`	`+ if (allowPositiveResult && result > (int)GitErrorCode.GIT_SUCCESS)`
`46`	`59`	`{`
`47`	`60`	`return;`
`48`	`61`	`}`
`@@ -65,7 +78,7 @@ public static void ArgumentConformsTo<T>(T argumentValue, Func<T, bool> checker,`
`65`	`78`	`{`
`66`	`79`	`return;`
`67`	`80`	`}`
`68`		`-`
	`81`	`+`
`69`	`82`	`throw new ArgumentException(argumentName);`
`70`	`83`	`}`
`71`	`84`	`}`
Original file line number	Diff line number	Diff line change
`@@ -30,7 +30,10 @@ public IndexEntry this[string path]`
`30`	`30`	`{`
`31`	`31`	`Ensure.ArgumentNotNullOrEmptyString(path, "path");`
`32`	`32`
`33`		`- return this[NativeMethods.git_index_find(handle, path)];`
	`33`	`+ int res = NativeMethods.git_index_find(handle, path);`
	`34`	`+ Ensure.Success(res, true);`
	`35`	`+`
	`36`	`+ return this[res];`
`34`	`37`	`}`
`35`	`38`	`}`
`36`	`39`