sftp: add single merge tests for both local <-> sftp and sftp <-> local

Had to fixup the symlink code in Sftp, most importantly add a PathUtils
relativeTo to fixup relative links.

1 files changed, 27 insertions, 0 deletions

diff --git a/libs/utils/src/main/java/org/the_jk/cleversync/PathUtils.kt b/libs/utils/src/main/java/org/the_jk/cleversync/PathUtils.kt
index 4202b24..77037cd 100644
--- a/libs/utils/src/main/java/org/the_jk/cleversync/PathUtils.kt
+++ b/libs/utils/src/main/java/org/the_jk/cleversync/PathUtils.kt
@@ -1,5 +1,7 @@
 package org.the_jk.cleversync
 
+import kotlin.math.min
+
 object PathUtils {
     fun dirname(path: String): String {
         if (path.isEmpty()) return "."
@@ -46,4 +48,29 @@ object PathUtils {
         }
         return parts.joinToString("/", prefix = if (prefixed) "/" else "")
     }
+
+    // Return path relative to base. Returns path as-is if either path is not
+    // absolute.
+    fun relativeTo(base: String, path: String): String {
+        if (!base.startsWith('/') || !path.startsWith('/')) return path
+        val baseParts = base.split('/').filter { part ->
+            part.isNotEmpty() && part != "."
+        }
+        val pathParts = path.split('/').filter { part ->
+            part.isNotEmpty() && part != "."
+        }
+        var i = 0
+        while (i < min(baseParts.size, pathParts.size)) {
+            if (baseParts[i] != pathParts[i]) break
+            i++
+        }
+        if (i == baseParts.size) {
+            if (i == pathParts.size) return "."
+            return pathParts.subList(i, pathParts.size).joinToString("/")
+        }
+        return buildList {
+            repeat(baseParts.size - i) { add("..") }
+            addAll(pathParts.subList(i, pathParts.size))
+        }.joinToString("/")
+    }
 }