From: Joel Rosdahl <joel@rosdahl.net>
Date: Thu, 20 Feb 2020 20:20:07 +0000 (+0100)
Subject: Add Stat::same_inode_as method
X-Git-Tag: v4.0~591
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=7caa6c00710844800763534fa2b6654c5da804f8;p=thirdparty%2Fccache.git

Add Stat::same_inode_as method
---

diff --git a/src/Stat.hpp b/src/Stat.hpp
index 19550c20b..9f9fa1601 100644
--- a/src/Stat.hpp
+++ b/src/Stat.hpp
@@ -61,6 +61,10 @@ public:
   // otherwise false.
   operator bool() const;
 
+  // Return whether this object refers to the same device and i-node as `other`
+  // does.
+  bool same_inode_as(const Stat& other) const;
+
   // Return errno from the (l)stat call (0 if successful).
   int error_number() const;
 
@@ -85,6 +89,9 @@ protected:
 private:
   struct stat m_stat;
   int m_errno;
+
+  bool operator==(const Stat&) const;
+  bool operator!=(const Stat&) const;
 };
 
 inline Stat::Stat() : m_stat{}, m_errno(-1)
@@ -115,6 +122,12 @@ inline Stat::operator bool() const
   return m_errno == 0;
 }
 
+inline bool
+Stat::same_inode_as(const Stat& other) const
+{
+  return device() == other.device() && inode() == other.inode();
+}
+
 inline int
 Stat::error_number() const
 {
diff --git a/unittest/test_Stat.cpp b/unittest/test_Stat.cpp
index 9f5c6ad16..ba140bd8a 100644
--- a/unittest/test_Stat.cpp
+++ b/unittest/test_Stat.cpp
@@ -52,6 +52,25 @@ TEST_CASE("Named constructors")
     Equals("failed to stat does_not_exist: No such file or directory"));
 }
 
+TEST_CASE("Same i-node as")
+{
+  Util::write_file("a", "");
+  Util::write_file("b", "");
+  auto a_stat = Stat::stat("a");
+  auto b_stat = Stat::stat("b");
+
+  CHECK(a_stat.same_inode_as(a_stat));
+#ifdef _WIN32 // no i-node concept
+  (void)b_stat;
+#else
+  CHECK(!a_stat.same_inode_as(b_stat));
+#endif
+
+  Util::write_file("a", "change size");
+  auto new_a_stat = Stat::stat("a");
+  CHECK(new_a_stat.same_inode_as(a_stat));
+}
+
 TEST_CASE("Return values when file is missing")
 {
   auto stat = Stat::stat("does_not_exist");