libsupport: URI prefix checking

Add methods to URI to check if one URI is a prefix of another.
KatanaGraph · Mar 11, 2022 · 056f20d · 056f20d
1 parent 1cd6985
commit 056f20d
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Showing 3 changed files with 31 additions and 1 deletion.
diff --git a/libsupport/include/katana/URI.h b/libsupport/include/katana/URI.h
@@ -32,6 +32,7 @@ class KATANA_EXPORT URI {
   /// 3. KATANA_TMPDIR
   /// The contents of the "most senior" set variable from this list will be used
   /// if any are set.
+  // TODO (scober): Add a signal handler to clear this directory
   static Result<URI> MakeTempDir();
 
   static std::string JoinPath(const std::string& dir, const std::string& file);
@@ -72,6 +73,15 @@ class KATANA_EXPORT URI {
   /// An overload of RandFile provided for clarity at call sites
   URI RandSubdir(std::string_view prefix) const { return RandFile(prefix); }
 
+  bool IsPrefixOf(const URI& other) const {
+    return scheme_ == other.scheme_ &&
+           other.path_.compare(0, path_.size(), path_) == 0;
+  }
+  bool HasAsPrefix(const URI& other) const {
+    return scheme_ == other.scheme_ &&
+           path_.compare(0, other.path_.size(), other.path_) == 0;
+  }
+
   URI operator+(char rhs) const;
   URI operator+(const std::string& rhs) const;
 

diff --git a/libsupport/src/URI.cpp b/libsupport/src/URI.cpp
@@ -281,7 +281,9 @@ katana::URI::MakeTempDir() {
   GetEnv("TMPDIR", &tmp_dir);
   GetEnv("KATANA_TMPDIR", &tmp_dir);
 
-  return KATANA_CHECKED(Make(tmp_dir));
+  auto tmp_uri = KATANA_CHECKED(Make(tmp_dir));
+
+  return tmp_uri.Join("katana-tmp");
 }
 
 std::string

diff --git a/libsupport/test/uri.cpp b/libsupport/test/uri.cpp
@@ -75,6 +75,22 @@ TestDecode() {
       katana::URI::Decode("host%3A8020/path") == "host:8020/path");
 }
 
+void
+TestPrefix() {
+  katana::URI full = Str2Uri("abc/def/ghi");
+  katana::URI prefix = Str2Uri("abc/d");
+  katana::URI not_prefix = Str2Uri("jkl/mn");
+  katana::URI other_not_prefix = Str2Uri("s3://abc/def");
+
+  KATANA_LOG_ASSERT(prefix.IsPrefixOf(full));
+  KATANA_LOG_ASSERT(full.HasAsPrefix(prefix));
+
+  KATANA_LOG_ASSERT(!not_prefix.IsPrefixOf(full));
+  KATANA_LOG_ASSERT(!full.HasAsPrefix(not_prefix));
+  KATANA_LOG_ASSERT(!other_not_prefix.IsPrefixOf(full));
+  KATANA_LOG_ASSERT(!full.HasAsPrefix(other_not_prefix));
+}
+
 }  // namespace
 
 int
@@ -87,5 +103,7 @@ main() {
 
   TestDecode();
 
+  TestPrefix();
+
   return 0;
 }