1 files changed, 121 insertions, 0 deletions
diff --git a/third_party/nix/src/libexpr/names.cc b/third_party/nix/src/libexpr/names.cc
new file mode 100644
index 0000000000..1e9c2f2f4a
--- /dev/null
+++ b/third_party/nix/src/libexpr/names.cc
@@ -0,0 +1,121 @@
+#include "libexpr/names.hh"
+
+#include <memory>
+
+#include <absl/strings/numbers.h>
+
+#include "libutil/util.hh"
+
+namespace nix {
+
+DrvName::DrvName() { name = ""; }
+
+/* Parse a derivation name.  The `name' part of a derivation name is
+   everything up to but not including the first dash *not* followed by
+   a letter.  The `version' part is the rest (excluding the separating
+   dash).  E.g., `apache-httpd-2.0.48' is parsed to (`apache-httpd',
+   '2.0.48'). */
+DrvName::DrvName(const std::string& s) : hits(0) {
+  name = fullName = s;
+  for (unsigned int i = 0; i < s.size(); ++i) {
+    /* !!! isalpha/isdigit are affected by the locale. */
+    if (s[i] == '-' && i + 1 < s.size() && (isalpha(s[i + 1]) == 0)) {
+      name = std::string(s, 0, i);
+      version = std::string(s, i + 1);
+      break;
+    }
+  }
+}
+
+bool DrvName::matches(DrvName& n) {
+  if (name != "*") {
+    if (!regex) {
+      regex = std::make_unique<std::regex>(name, std::regex::extended);
+    }
+    if (!std::regex_match(n.name, *regex)) {
+      return false;
+    }
+  }
+  return !(!version.empty() && version != n.version);
+}
+
+std::string nextComponent(std::string::const_iterator& p,
+                          const std::string::const_iterator end) {
+  /* Skip any dots and dashes (component separators). */
+  while (p != end && (*p == '.' || *p == '-')) {
+    ++p;
+  }
+
+  if (p == end) {
+    return "";
+  }
+
+  /* If the first character is a digit, consume the longest sequence
+     of digits.  Otherwise, consume the longest sequence of
+     non-digit, non-separator characters. */
+  std::string s;
+  if (isdigit(*p) != 0) {
+    while (p != end && (isdigit(*p) != 0)) {
+      s += *p++;
+    }
+  } else {
+    while (p != end && ((isdigit(*p) == 0) && *p != '.' && *p != '-')) {
+      s += *p++;
+    }
+  }
+
+  return s;
+}
+
+static bool componentsLT(const std::string& c1, const std::string& c2) {
+  int n1;
+  int n2;
+  bool c1Num = absl::SimpleAtoi(c1, &n1);
+  bool c2Num = absl::SimpleAtoi(c2, &n2);
+
+  if (c1Num && c2Num) {
+    return n1 < n2;
+  }
+  if (c1.empty() && c2Num) {
+    return true;
+  } else if (c1 == "pre" && c2 != "pre") {
+    return true;
+  } else if (c2 == "pre") {
+    return false;
+    /* Assume that `2.3a' < `2.3.1'. */
+  } else if (c2Num) {
+    return true;
+  } else if (c1Num) {
+    return false;
+  } else {
+    return c1 < c2;
+  }
+}
+
+int compareVersions(const std::string& v1, const std::string& v2) {
+  std::string::const_iterator p1 = v1.begin();
+  std::string::const_iterator p2 = v2.begin();
+
+  while (p1 != v1.end() || p2 != v2.end()) {
+    std::string c1 = nextComponent(p1, v1.end());
+    std::string c2 = nextComponent(p2, v2.end());
+    if (componentsLT(c1, c2)) {
+      return -1;
+    }
+    if (componentsLT(c2, c1)) {
+      return 1;
+    }
+  }
+
+  return 0;
+}
+
+DrvNames drvNamesFromArgs(const Strings& opArgs) {
+  DrvNames result;
+  for (auto& i : opArgs) {
+    result.push_back(DrvName(i));
+  }
+  return result;
+}
+
+}  // namespace nix