Do not gather full input data in a single string when piping

Refactor ShellManager and pipe to feed lines from the buffer directly,
this should reduce memory use when piping big chunks of buffers.

The pipe output is still provided as a single big buffer.

1 files changed, 23 insertions, 12 deletions

diff --git a/src/normal.cc b/src/normal.cc
index 689137ef..056f11de 100644
--- a/src/normal.cc
+++ b/src/normal.cc
@@ -535,9 +535,8 @@ void command(Context& context, NormalParams params)
     command(context, std::move(env_vars), params.reg);
 }
 
-BufferCoord apply_diff(Buffer& buffer, BufferCoord pos, StringView before, StringView after)
+BufferCoord apply_diff(Buffer& buffer, BufferCoord pos, ArrayView<StringView> lines_before, StringView after)
 {
-    const auto lines_before = before | split_after<StringView>('\n') | gather<Vector<StringView>>();
     const auto lines_after = after | split_after<StringView>('\n') | gather<Vector<StringView>>();
 
     auto byte_count = [](auto&& lines, int first, int count) {
@@ -601,26 +600,38 @@ void pipe(Context& context, NormalParams params)
                 SelectionList selections = context.selections();
                 for (auto& sel : selections)
                 {
-                    const auto beg = changes_tracker.get_new_coord_tolerant(sel.min());
-                    const auto end = changes_tracker.get_new_coord_tolerant(sel.max());
+                    const auto first = changes_tracker.get_new_coord_tolerant(sel.min());
+                    const auto last = changes_tracker.get_new_coord_tolerant(sel.max());
+
+                    Vector<StringView> in_lines;
+                    for (auto line = first.line; line <= last.line; ++line)
+                    {
+                        auto content = buffer[line];
+                        if (line == last.line)
+                            content = content.substr(0, last.column + utf8::codepoint_size(content[last.column]));
+                        if (line == first.line)
+                            content = content.substr(first.column);
+                        in_lines.push_back(content);
+                    }
 
-                    String in = buffer.string(beg, buffer.char_next(end));
                     // Needed in case we read selections inside the cmdline
-                    context.selections_write_only().set({keep_direction(Selection{beg, end}, sel)}, 0);
+                    context.selections_write_only().set({keep_direction(Selection{first, last}, sel)}, 0);
 
                     String out = ShellManager::instance().eval(
-                        cmdline, context, in,
-                        ShellManager::Flags::WaitForStdout).first;
+                        cmdline, context,
+                        [it = in_lines.begin(), end = in_lines.end()]() mutable {
+                            return (it != end) ? *it++ : StringView{};
+                        }, ShellManager::Flags::WaitForStdout).first;
 
-                    if (in.back() != '\n' and not out.empty() and out.back() == '\n')
+                    if (in_lines.back().back() != '\n' and not out.empty() and out.back() == '\n')
                         out.resize(out.length()-1, 0);
 
-                    auto new_end = apply_diff(buffer, beg, in, out);
-                    if (new_end != beg)
+                    auto new_end = apply_diff(buffer, first, in_lines, out);
+                    if (new_end != first)
                     {
                         auto& min = sel.min();
                         auto& max = sel.max();
-                        min = beg;
+                        min = first;
                         max = buffer.char_prev(new_end);
                     }
                     else