Add 'history' and 'uncommitted_modifications' expansions

10 files changed, 119 insertions, 28 deletions

diff --git a/doc/pages/expansions.asciidoc b/doc/pages/expansions.asciidoc
index cda11e73..5156e293 100644
--- a/doc/pages/expansions.asciidoc
+++ b/doc/pages/expansions.asciidoc
@@ -258,6 +258,18 @@ The following expansions are supported (with required context _in italics_):
     the text of the error that cancelled execution of the <commands> parameter
     (or the previous <on_error_commands> parameter)
 
+*%val{history}*::
+    _in buffer, window scope_ +
+    the full change history of the buffer, including undo forks, in terms
+    of `parent committed redo_child modification0 modification1 ...`
+    entries, where _parent_ is the index of the entry's predecessor (entry
+    0, which is the root of the history tree, will always have `-` here),
+    _committed_ is a count in seconds from Kakoune's steady clock's epoch
+    of the  creation of the history entry, _redo_child_ is the index of the
+    child which will be visited for `U` (always `-` at the leaves of the
+    history), and each _modification_ is presented as in
+    `%val{uncommited_changes}`.
+
 *%val{history_id}*::
     _in buffer, window scope_ +
     history id of the current buffer, an integer value which refers to a
@@ -353,6 +365,15 @@ The following expansions are supported (with required context _in italics_):
     buffer is modified, including undoing and redoing previous modifications
     (see also `%val{history_id}`)
 
+*%val{uncommitted_modifications}*::
+    _in buffer, window scope_ +
+    a list of quoted insertions (in the format `+line.column|text`) and
+    deletions (`-line.column|text`) not yet saved to the history (e.g. typing
+    in insert mode before pressing `<esc>`), where _line_ is the 1-based line
+    of the change, _column_ is the 1-based _byte_ of the change start (see
+    `%val{cursor_column}`), and _text_ is the content of the insertion or
+    deletion (see also `%val{history}`)
+
 *%val{user_modes}*::
     unquoted list of user modes.
 
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); }
     }
 };
 
diff --git a/test/compose/history/cmd b/test/compose/history/cmd
new file mode 100644
index 00000000..13d71626
--- /dev/null
+++ b/test/compose/history/cmd
@@ -0,0 +1 @@
+Amiddle<esc><a-f>dd
diff --git a/test/compose/history/in b/test/compose/history/in
new file mode 100644
index 00000000..d44e18fb
--- /dev/null
+++ b/test/compose/history/in
@@ -0,0 +1 @@
+start
diff --git a/test/compose/history/kak_quoted_history b/test/compose/history/kak_quoted_history
new file mode 100644
index 00000000..acd0fedc
--- /dev/null
+++ b/test/compose/history/kak_quoted_history
@@ -0,0 +1 @@
+- $timestamp 1 0 $timestamp - '+0.5|m' '+0.6|i' '+0.7|d' '+0.8|d' '+0.9|l' '+0.10|e' '-0.8|dle'
diff --git a/test/compose/history/rc b/test/compose/history/rc
new file mode 100644
index 00000000..931d0d1c
--- /dev/null
+++ b/test/compose/history/rc
@@ -0,0 +1,7 @@
+# Make our expansion have a predictable timestamp
+hook global ClientClose .* %{
+    evaluate-commands %sh{
+        kak -f 'ghf<space>ec$timestamp<esc>2f<space>ec$timestamp<esc>' <kak_quoted_history >tmp
+        mv tmp kak_quoted_history
+    }
+}