Move PodIdx to pos-idx.hh and PosTable to pos-table.hh

(cherry picked from commit c62c21e29af20f1c14a59ab37d7a25dd0b70f69e)
Change-Id: Id4ea2fc33b0874b2f1f2a32cabcbeb0afa26808f

src/libexpr/nixexpr.hh

@@ -9,6 +9,8 @@
 #include "error.hh"
 #include "chunked-vector.hh"
 #include "position.hh"
+#include "pos-idx.hh"
+#include "pos-table.hh"
 
 namespace nix {
 
@@ -30,90 +32,6 @@ public:
     using EvalError::EvalError;
 };
 
-class PosIdx {
-    friend class PosTable;
-
-private:
-    uint32_t id;
-
-    explicit PosIdx(uint32_t id): id(id) {}
-
-public:
-    PosIdx() : id(0) {}
-
-    explicit operator bool() const { return id > 0; }
-
-    bool operator <(const PosIdx other) const { return id < other.id; }
-
-    bool operator ==(const PosIdx other) const { return id == other.id; }
-
-    bool operator !=(const PosIdx other) const { return id != other.id; }
-};
-
-class PosTable
-{
-public:
-    class Origin {
-        friend PosTable;
-    private:
-        // must always be invalid by default, add() replaces this with the actual value.
-        // subsequent add() calls use this index as a token to quickly check whether the
-        // current origins.back() can be reused or not.
-        mutable uint32_t idx = std::numeric_limits<uint32_t>::max();
-
-        // Used for searching in PosTable::[].
-        explicit Origin(uint32_t idx): idx(idx), origin{std::monostate()} {}
-
-    public:
-        const Pos::Origin origin;
-
-        Origin(Pos::Origin origin): origin(origin) {}
-    };
-
-    struct Offset {
-        uint32_t line, column;
-    };
-
-private:
-    std::vector<Origin> origins;
-    ChunkedVector<Offset, 8192> offsets;
-
-public:
-    PosTable(): offsets(1024)
-    {
-        origins.reserve(1024);
-    }
-
-    PosIdx add(const Origin & origin, uint32_t line, uint32_t column)
-    {
-        const auto idx = offsets.add({line, column}).second;
-        if (origins.empty() || origins.back().idx != origin.idx) {
-            origin.idx = idx;
-            origins.push_back(origin);
-        }
-        return PosIdx(idx + 1);
-    }
-
-    Pos operator[](PosIdx p) const
-    {
-        if (p.id == 0 || p.id > offsets.size())
-            return {};
-        const auto idx = p.id - 1;
-        /* we want the last key <= idx, so we'll take prev(first key > idx).
-           this is guaranteed to never rewind origin.begin because the first
-           key is always 0. */
-        const auto pastOrigin = std::upper_bound(
-            origins.begin(), origins.end(), Origin(idx),
-            [] (const auto & a, const auto & b) { return a.idx < b.idx; });
-        const auto origin = *std::prev(pastOrigin);
-        const auto offset = offsets[idx];
-        return {offset.line, offset.column, origin.origin};
-    }
-};
-
-inline PosIdx noPos = {};
-
-
 struct Env;
 struct Value;
 class EvalState;

src/libexpr/pos-idx.hh

@@ -0,0 +1,48 @@
+#pragma once
+
+#include <cinttypes>
+
+namespace nix {
+
+class PosIdx
+{
+    friend class PosTable;
+
+private:
+    uint32_t id;
+
+    explicit PosIdx(uint32_t id)
+        : id(id)
+    {
+    }
+
+public:
+    PosIdx()
+        : id(0)
+    {
+    }
+
+    explicit operator bool() const
+    {
+        return id > 0;
+    }
+
+    bool operator<(const PosIdx other) const
+    {
+        return id < other.id;
+    }
+
+    bool operator==(const PosIdx other) const
+    {
+        return id == other.id;
+    }
+
+    bool operator!=(const PosIdx other) const
+    {
+        return id != other.id;
+    }
+};
+
+inline PosIdx noPos = {};
+
+}

src/libexpr/pos-table.hh

@@ -0,0 +1,83 @@
+#pragma once
+
+#include <cinttypes>
+#include <numeric>
+#include <vector>
+
+#include "chunked-vector.hh"
+#include "pos-idx.hh"
+#include "position.hh"
+
+namespace nix {
+
+class PosTable
+{
+public:
+    class Origin
+    {
+        friend PosTable;
+    private:
+        // must always be invalid by default, add() replaces this with the actual value.
+        // subsequent add() calls use this index as a token to quickly check whether the
+        // current origins.back() can be reused or not.
+        mutable uint32_t idx = std::numeric_limits<uint32_t>::max();
+
+        // Used for searching in PosTable::[].
+        explicit Origin(uint32_t idx)
+            : idx(idx)
+            , origin{std::monostate()}
+        {
+        }
+
+    public:
+        const Pos::Origin origin;
+
+        Origin(Pos::Origin origin)
+            : origin(origin)
+        {
+        }
+    };
+
+    struct Offset
+    {
+        uint32_t line, column;
+    };
+
+private:
+    std::vector<Origin> origins;
+    ChunkedVector<Offset, 8192> offsets;
+
+public:
+    PosTable()
+        : offsets(1024)
+    {
+        origins.reserve(1024);
+    }
+
+    PosIdx add(const Origin & origin, uint32_t line, uint32_t column)
+    {
+        const auto idx = offsets.add({line, column}).second;
+        if (origins.empty() || origins.back().idx != origin.idx) {
+            origin.idx = idx;
+            origins.push_back(origin);
+        }
+        return PosIdx(idx + 1);
+    }
+
+    Pos operator[](PosIdx p) const
+    {
+        if (p.id == 0 || p.id > offsets.size())
+            return {};
+        const auto idx = p.id - 1;
+        /* we want the last key <= idx, so we'll take prev(first key > idx).
+           this is guaranteed to never rewind origin.begin because the first
+           key is always 0. */
+        const auto pastOrigin = std::upper_bound(
+            origins.begin(), origins.end(), Origin(idx), [](const auto & a, const auto & b) { return a.idx < b.idx; });
+        const auto origin = *std::prev(pastOrigin);
+        const auto offset = offsets[idx];
+        return {offset.line, offset.column, origin.origin};
+    }
+};
+
+}