Initial commit

1 files changed, 98 insertions, 0 deletions

diff --git a/src/paths.cc b/src/paths.cc
new file mode 100644
index 0000000..095076f
--- /dev/null
+++ b/src/paths.cc
@@ -0,0 +1,98 @@
+// -*- mode: c++; c-basic-offset: 2; -*-
+
+#include "common.hh"
+
+#include "paths.hh"
+
+// static
+std::string Paths::join(std::string const& base, std::string const& path) {
+  if (path.empty()) {
+    return cleanup(base);
+  } else if (path.front() == '/') {
+    return cleanup(path);
+  }
+  std::string ret(cleanup(base));
+  if (ret == ".") {
+    return cleanup(path);
+  }
+  if (ret.empty() || ret.back() != '/') {
+    ret.push_back('/');
+  }
+  ret.append(cleanup(path));
+  return ret;
+}
+
+namespace {
+
+std::string do_cleanup(std::string const& path) {
+  size_t i = 0, j = 0;
+  std::string ret;
+  bool add_slash = false;
+  if (path.front() == '/') {
+    ret.push_back('/');
+    i = j = 1;
+  }
+  while (true) {
+    if (j == path.size() || path[j] == '/') {
+      auto len = j - i;
+      if (len > 0) {
+        if (len == 1 && path[i] == '.') {
+          i = ++j;
+          continue;
+        }
+        if (add_slash && len == 2 && path[i] == '.' && path[i + 1] == '.') {
+          auto x = ret.find_last_of('/');
+          if (x == std::string::npos) x = 0;
+          ret.erase(x);
+          add_slash = !(ret.empty() || ret == "/");
+          i = ++j;
+          continue;
+        }
+        if (add_slash) {
+          ret.push_back('/');
+        } else {
+          add_slash = true;
+        }
+        ret.append(path.substr(i, len));
+      }
+      if (j == path.size()) {
+        return ret;
+      }
+      i = ++j;
+    } else {
+      ++j;
+    }
+  }
+}
+
+}  // namespace
+
+// static
+std::string Paths::cleanup(std::string const& path) {
+  if (path.empty()) return ".";
+  if (path[0] == '.') {
+    if (path.size() == 1) return path;
+    if (path[1] == '/') return do_cleanup(path);  // found ./ at beginning
+  }
+  for (size_t pos = 0; pos < path.size(); ++pos) {
+    if (path[pos] == '/') {
+      if (pos > 0 && pos + 1 == path.size()) {
+        // found slash at end
+        return path.substr(0, path.size() - 1);
+      }
+      if (path[pos + 1] == '/') return do_cleanup(path);  // found double slash
+      if (path[pos + 1] == '.') {
+        if (pos + 2 == path.size()) return do_cleanup(path);  // found /. at end
+        if (path[pos + 2] == '/') return do_cleanup(path);  // found /./
+        if (path[pos + 2] == '.') {
+          if (pos + 3 == path.size()) {
+            // found /.. at end
+            return do_cleanup(path);
+          }
+          if (path[pos + 3] == '/') do_cleanup(path);  // found /../
+        }
+      }
+    }
+  }
+  return path;
+}