Add 'history' and 'uncommitted_modifications' expansions

5 files changed, 88 insertions, 28 deletions

diff --git a/src/buffer.cc b/src/buffer.cc
index f7eeee31..c2a04c2e 100644
--- a/src/buffer.cc
+++ b/src/buffer.cc
@@ -66,7 +66,7 @@ static void apply_options(OptionManager& options, const ParsedLines& parsed_line
 }
 
 Buffer::HistoryNode::HistoryNode(HistoryId parent)
-    : parent{parent}, timepoint{Clock::now()}
+    : parent{parent}, committed{Clock::now()}
 {}
 
 Buffer::Buffer(String name, Flags flags, StringView data,
@@ -231,20 +231,10 @@ String Buffer::string(BufferCoord begin, BufferCoord end) const
     return res;
 }
 
-// A Modification holds a single atomic modification to Buffer
-struct Buffer::Modification
+Buffer::Modification Buffer::Modification::inverse() const
 {
-    enum Type { Insert, Erase };
-
-    Type type;
-    BufferCoord coord;
-    StringDataPtr content;
-
-    Modification inverse() const
-    {
-        return {type == Insert ? Erase : Insert, coord, content};
-    }
-};
+    return {type == Insert ? Erase : Insert, coord, content};
+}
 
 void Buffer::reload(StringView data, timespec fs_timestamp)
 {
diff --git a/src/buffer.hh b/src/buffer.hh
index 0700acb9..73e5b370 100644
--- a/src/buffer.hh
+++ b/src/buffer.hh
@@ -230,14 +230,40 @@ public:
     void on_unregistered();
 
     void throw_if_read_only() const;
+
+    // A Modification holds a single atomic modification to Buffer
+    struct Modification
+    {
+        enum Type { Insert, Erase };
+
+        Type type;
+        BufferCoord coord;
+        StringDataPtr content;
+
+        Modification inverse() const;
+    };
+
+    using UndoGroup = Vector<Modification, MemoryDomain::BufferMeta>;
+
+    struct HistoryNode : UseMemoryDomain<MemoryDomain::BufferMeta>
+    {
+        HistoryNode(HistoryId parent);
+
+        HistoryId parent;
+        HistoryId redo_child = HistoryId::Invalid;
+        TimePoint committed;
+        UndoGroup undo_group;
+    };
+
+    const Vector<HistoryNode>& history() const { return m_history; }
+    const UndoGroup& current_undo_group() const { return m_current_undo_group; }
+
 private:
     void on_option_changed(const Option& option) override;
 
     BufferRange do_insert(BufferCoord pos, StringView content);
     BufferCoord do_erase(BufferCoord begin, BufferCoord end);
 
-    struct Modification;
-
     void apply_modification(const Modification& modification);
     void revert_modification(const Modification& modification);
 
@@ -264,18 +290,6 @@ private:
     String m_display_name;
     Flags  m_flags;
 
-    using UndoGroup = Vector<Modification, MemoryDomain::BufferMeta>;
-
-    struct HistoryNode : UseMemoryDomain<MemoryDomain::BufferMeta>
-    {
-        HistoryNode(HistoryId parent);
-
-        HistoryId parent;
-        HistoryId redo_child = HistoryId::Invalid;
-        TimePoint timepoint;
-        UndoGroup undo_group;
-    };
-
     Vector<HistoryNode> m_history;
     HistoryId           m_history_id = HistoryId::Invalid;
     HistoryId           m_last_save_history_id = HistoryId::Invalid;
diff --git a/src/buffer_utils.cc b/src/buffer_utils.cc
index 4b6c3763..1d3d350d 100644
--- a/src/buffer_utils.cc
+++ b/src/buffer_utils.cc
@@ -213,4 +213,47 @@ void write_to_debug_buffer(StringView str)
     }
 }
 
+InplaceString<23> to_string(Buffer::HistoryId id)
+{
+    if (id == Buffer::HistoryId::Invalid) {
+        InplaceString<23> res;
+        res.m_data[0] = '-';
+        res.m_length = 1;
+        return res;
+    } else {
+        return to_string(static_cast<size_t>(id));
+    }
+}
+
+String format_modification(const Buffer::Modification& modification, Quoting quoting)
+{
+    auto quote = quoter(quoting);
+    return quote(format("{}{}.{}|{}",
+                        modification.type == Buffer::Modification::Type::Insert ? '+' : '-',
+                        modification.coord.line, modification.coord.column,
+                        modification.content->strview()));
+}
+
+String history_as_string(const Vector<Buffer::HistoryNode>& history, Quoting quoting)
+{
+    auto format_history_node = [&](const Buffer::HistoryNode& node) {
+        auto seconds = std::chrono::duration_cast<std::chrono::seconds>(node.committed.time_since_epoch());
+        return format("{} {} {}{}{}",
+                      node.parent,
+                      seconds.count(),
+                      node.redo_child,
+                      node.undo_group.empty() ? "" : " ",
+                      undo_group_as_string(node.undo_group, quoting));
+    };
+    return join(history |transform(format_history_node), ' ', false);
+}
+
+String undo_group_as_string(const Buffer::UndoGroup& undo_group, Quoting quoting)
+{
+    auto modification_as_string = [&](const Buffer::Modification& modification) {
+        return format_modification(modification, quoting);
+    };
+    return join(undo_group |transform(modification_as_string), ' ', false);
+}
+
 }
diff --git a/src/buffer_utils.hh b/src/buffer_utils.hh
index a3e43068..a7589864 100644
--- a/src/buffer_utils.hh
+++ b/src/buffer_utils.hh
@@ -84,6 +84,11 @@ void reload_file_buffer(Buffer& buffer);
 
 void write_to_debug_buffer(StringView str);
 
+InplaceString<23> to_string(Buffer::HistoryId id);
+String format_modification(const Buffer::Modification& modification, Quoting quoting);
+String history_as_string(const Vector<Buffer::HistoryNode>& history, Quoting quoting);
+String undo_group_as_string(const Buffer::UndoGroup& undo_group, Quoting quoting);
+
 }
 
 #endif // buffer_utils_hh_INCLUDED
diff --git a/src/main.cc b/src/main.cc
index 84c88012..621b5350 100644
--- a/src/main.cc
+++ b/src/main.cc
@@ -309,6 +309,14 @@ static const EnvVarDesc builtin_env_vars[] = { {
             return format("{} {} {} {}", setup.window_pos.line, setup.window_pos.column,
                                          setup.window_range.line, setup.window_range.column);
         }
+    }, {
+        "history", false,
+        [](StringView name, const Context& context, Quoting quoting) -> String
+        { return history_as_string(context.buffer().history(), quoting); }
+    }, {
+        "uncommitted_modifications", false,
+        [](StringView name, const Context& context, Quoting quoting) -> String
+        { return undo_group_as_string(context.buffer().current_undo_group(), quoting); }
     }
 };