Add support for `@` symbols in selection buffer

The selection descriptions use the format
`<buffer>@<timestamp>@<main_index>`. This fails when file paths have `@`
symbols in them: the parser splits on `@` symbols and finds more values
than it expects.

We here modify the behavior to require *at least* two @ symbols, using
the last two for `<timestamp>` and `<main_index>` and leaving the
remaining text for the <buffer>. This should work for any number of `@`
symbols, since `<timestamp>` and `<main_index>` are numbers and should
never contain `@` symbols.

2 files changed, 34 insertions, 5 deletions

diff --git a/src/normal.cc b/src/normal.cc
index f9b1184f..2c00fb63 100644
--- a/src/normal.cc
+++ b/src/normal.cc
@@ -1,5 +1,7 @@
 #include "normal.hh"
 
+#include <functional>
+
 #include "buffer.hh"
 #include "buffer_manager.hh"
 #include "buffer_utils.hh"
@@ -1774,11 +1776,20 @@ SelectionList read_selections_from_register(char reg, Context& context)
     if (content.size() < 2)
         throw runtime_error(format("register '{}' does not contain a selections desc", reg));
 
-    struct error : runtime_error { error(size_t) : runtime_error{"expected <buffer>@<timestamp>@main_index"} {} };
-    const auto desc = content[0] | split<StringView>('@') | static_gather<error, 3>();
-    Buffer& buffer = BufferManager::instance().get_buffer(desc[0]);
-    const size_t timestamp = str_to_int(desc[1]);
-    size_t main = str_to_int(desc[2]);
+    // Use the last two values for timestamp and main_index to allow the buffer
+    // name to have @ symbols
+    struct error : runtime_error { error() : runtime_error{"expected <buffer>@<timestamp>@main_index"} {} };
+    const auto desc = content[0] | split<StringView>('@') | gather<Vector>();
+    const size_t desc_size = desc.size();
+    if (desc_size < 3)
+        throw new error;
+    auto const buffer_name_view = desc | drop(2);
+    auto const buffer_name_temp = accumulate (buffer_name_view, ""_str,
+        [](auto str1, auto str2) { return str1 + "@"_str + str2; });
+    auto const buffer_name = buffer_name_temp.substr (CharCount (1));
+    Buffer& buffer = BufferManager::instance().get_buffer(buffer_name);
+    const size_t timestamp = str_to_int(desc[desc_size - 2]);
+    size_t main = str_to_int(desc[desc_size - 1]);
 
     return selection_list_from_strings(buffer, ColumnType::Byte, content | skip(1), timestamp, main);
 }
diff --git a/src/ranges.hh b/src/ranges.hh
index 4cd85a25..6518e00e 100644
--- a/src/ranges.hh
+++ b/src/ranges.hh
@@ -73,6 +73,24 @@ inline auto skip(size_t count)
     });
 }
 
+template<typename Range>
+struct DropView
+{
+    auto begin() const { return std::begin(m_range); }
+    auto end()   const { return std::end(m_range) - m_drop_count; }
+
+    Range m_range;
+    size_t m_drop_count;
+};
+
+inline auto drop(size_t count)
+{
+    return make_view_factory([count](auto&& range) {
+        using Range = decltype(range);
+        return DropView<decay_range<Range>>{std::forward<Range>(range), count};
+    });
+}
+
 template<typename Range, typename Filter>
 struct FilterView
 {