From 56eaf9b033553d7537f1a22906fcdc7e1404bc26 Mon Sep 17 00:00:00 2001
From: Andreas Kling <awesomekling@gmail.com>
Date: Fri, 23 Aug 2019 19:55:51 +0200
Subject: [PATCH] AK: Make FileSystemPath better at handling relative paths

Relative paths now canonicalize into a string starting with "./"
Previously, "foo" would be canonicalized as "/foo" which was clearly
not right.
---
 AK/FileSystemPath.cpp           | 27 +++++++++++++++++++++------
 AK/Tests/TestFileSystemPath.cpp | 33 +++++++++++++++++++++++++++++++++
 2 files changed, 54 insertions(+), 6 deletions(-)

diff --git a/AK/FileSystemPath.cpp b/AK/FileSystemPath.cpp
index 72c7d1ff0b..8c95da826d 100644
--- a/AK/FileSystemPath.cpp
+++ b/AK/FileSystemPath.cpp
@@ -14,13 +14,26 @@ FileSystemPath::FileSystemPath(const StringView& s)
 
 void FileSystemPath::canonicalize()
 {
+    if (m_string.is_empty()) {
+        m_parts.clear();
+        return;
+    }
+
+    bool is_absolute_path = m_string[0] == '/';
     auto parts = m_string.split_view('/');
+
+    if (!is_absolute_path)
+        parts.prepend(".");
+
     int approximate_canonical_length = 0;
     Vector<String> canonical_parts;
 
-    for (auto& part : parts) {
-        if (part == ".")
-            continue;
+    for (int i = 0; i < parts.size(); ++i) {
+        auto& part = parts[i];
+        if (is_absolute_path || i != 0) {
+            if (part == ".")
+                continue;
+        }
         if (part == "..") {
             if (!canonical_parts.is_empty())
                 canonical_parts.take_last();
@@ -43,9 +56,11 @@ void FileSystemPath::canonicalize()
         m_extension = name_parts[1];
 
     StringBuilder builder(approximate_canonical_length);
-    for (auto& cpart : canonical_parts) {
-        builder.append('/');
-        builder.append(cpart);
+    for (int i = 0; i < canonical_parts.size(); ++i) {
+        auto& canonical_part = canonical_parts[i];
+        if (is_absolute_path || i != 0)
+            builder.append('/');
+        builder.append(canonical_part);
     }
     m_parts = move(canonical_parts);
     m_string = builder.to_string();
diff --git a/AK/Tests/TestFileSystemPath.cpp b/AK/Tests/TestFileSystemPath.cpp
index a3d29344ef..e019f53b16 100644
--- a/AK/Tests/TestFileSystemPath.cpp
+++ b/AK/Tests/TestFileSystemPath.cpp
@@ -26,4 +26,37 @@ TEST_CASE(dotdot_coalescing)
     EXPECT_EQ(FileSystemPath("/../../../../").string(), "/");
 }
 
+TEST_CASE(relative_paths)
+{
+    {
+        FileSystemPath path("simple");
+        EXPECT_EQ(path.is_valid(), true);
+        EXPECT_EQ(path.string(), "./simple");
+        EXPECT_EQ(path.parts().size(), 2);
+        EXPECT_EQ(path.basename(), "simple");
+    }
+    {
+        FileSystemPath path("a/relative/path");
+        EXPECT_EQ(path.is_valid(), true);
+        EXPECT_EQ(path.string(), "./a/relative/path");
+        EXPECT_EQ(path.parts().size(), 4);
+        EXPECT_EQ(path.basename(), "path");
+    }
+    {
+        FileSystemPath path("./././foo");
+        EXPECT_EQ(path.is_valid(), true);
+        EXPECT_EQ(path.string(), "./foo");
+        EXPECT_EQ(path.parts().size(), 2);
+        EXPECT_EQ(path.basename(), "foo");
+    }
+
+    {
+        FileSystemPath path(".");
+        EXPECT_EQ(path.is_valid(), true);
+        EXPECT_EQ(path.string(), ".");
+        EXPECT_EQ(path.parts().size(), 1);
+        EXPECT_EQ(path.basename(), ".");
+    }
+}
+
 TEST_MAIN(FileSystemPath)