tree: unique keys

to get around #10 each node in the tree now has a unique key.

marshaling the tree is updated to cache the node at all given lines every
time write_tree is called.

marshaling a line is greatly simplified and just looks at the cached now
to understand which node is being selected.

closes #10

Signed-off-by: ldelossa <louis.delos@gmail.com>

lua/calltree/tree.lua

@@ -32,10 +32,25 @@ function M.Node.new(name, depth, call_hierarchy_obj, kind, references)
         kind=kind,
         references=references
     }
+    node.key = M.Node.keyify(node)
     setmetatable(node, M.Node.mt)
     return node
 end
 
+-- keyify creates a key for a node
+--
+-- node : tree.Node - the node a key is being created
+-- for
+--
+-- returns:
+--  string - the key
+function M.Node.keyify(node)
+    local key = node.name .. ":"
+        .. node.call_hierarchy_obj.uri .. ":"
+        .. node.call_hierarchy_obj.range.start.line
+    return key
+end
+
 -- eq perfoms a recursive comparison
 -- between the two roots and their children.
 function M.Node.eq(a, b)
@@ -128,7 +143,7 @@ function M.add_node(parent,  children)
     -- lookup parent node in depth tree (faster then tree diving.)
     local pNode = nil
     for _, node in pairs(M.depth_table[parent.depth]) do
-        if node.name == parent.name then
+        if node.key == parent.key then
             pNode = node
             break
         end
@@ -193,7 +208,7 @@ function M.remove_subtree(node, root)
         local dt = M.depth_table[node.depth]
         local nw_dt = {}
         for _, dt_node in ipairs(dt) do
-            if dt_node.name ~= node.name then
+            if dt_node.key ~= node.key then
                 table.insert(nw_dt, dt_node)
             end
         end

lua/calltree/ui.lua

@@ -93,8 +93,7 @@ end
 -- position
 M.collapse = function()
     local linenr = vim.api.nvim_win_get_cursor(M.win_handle)
-    local line   = vim.api.nvim_get_current_line()
-    local node   = marshal.marshal_line(line)
+    local node   = marshal.marshal_line(linenr)
     if node == nil then
         return
     end
@@ -154,8 +153,7 @@ end
 -- expand will expand a symbol at the current cursor position
 M.expand = function()
     local linenr = vim.api.nvim_win_get_cursor(M.win_handle)
-    local line   = vim.api.nvim_get_current_line()
-    local node = marshal.marshal_line(line)
+    local node = marshal.marshal_line(linenr)
     if node == nil then
         return
     end
@@ -177,8 +175,8 @@ end
 -- the cursor, creating a calltree with the symbol
 -- as root.
 M.focus = function()
-    local line = vim.api.nvim_get_current_line()
-    local node = marshal.marshal_line(line)
+    local linenr = vim.api.nvim_win_get_cursor(M.win_handle)
+    local node = marshal.marshal_line(linenr)
     if node == nil then
         return
     end
@@ -229,8 +227,8 @@ end
 -- switch_direction will focus the symbol under the
 -- cursor and then invert the call hierarchy direction.
 M.switch_direction = function()
-    local line = vim.api.nvim_get_current_line()
-    local node = marshal.marshal_line(line)
+    local linenr = vim.api.nvim_win_get_cursor(M.win_handle)
+    local node = marshal.marshal_line(linenr)
     if node == nil then
         return
     end
@@ -253,8 +251,8 @@ end
 -- jump will jump to the source code location of the
 -- symbol under the cursor.
 M.jump = function()
-    local line = vim.api.nvim_get_current_line()
-    local node = marshal.marshal_line(line)
+    local linenr = vim.api.nvim_win_get_cursor(M.win_handle)
+    local node = marshal.marshal_line(linenr)
     if node == nil then
         return
     end
@@ -276,8 +274,8 @@ end
 -- under the cursor.
 M.hover = function()
     ui_buf.close_all_popups()
-    local line = vim.api.nvim_get_current_line()
-    local node = marshal.marshal_line(line)
+    local linenr = vim.api.nvim_win_get_cursor(M.win_handle)
+    local node = marshal.marshal_line(linenr)
     if node == nil then
         return
     end
@@ -297,8 +295,8 @@ end
 -- showing more information.
 M.details = function()
     ui_buf.close_all_popups()
-    local line = vim.api.nvim_get_current_line()
-    local node = marshal.marshal_line(line)
+    local linenr = vim.api.nvim_win_get_cursor(M.win_handle)
+    local node = marshal.marshal_line(linenr)
     if node == nil then
         return
     end

lua/calltree/ui/marshal.lua

@@ -10,6 +10,10 @@ M.glyphs = {
     separator = "•"
 }
 
+-- buf_line_map keeps a mapping between marshaled
+-- buffer lines and the node objects
+M.buf_line_map = {}
+
 -- marshal_node takes a node and marshals
 -- it into a UI buffer line.
 --
@@ -60,32 +64,14 @@ end
 -- marshal_line takes a UI buffer line and
 -- marshals it into a tree.Node.
 --
--- line : string - the UI buffer line representing
--- the node to marshal.
+-- linenr : {row,col} - the UI buffer line typically returned by
+-- vim.api.nvim_win_get_cursor(calltree_win_handle)
 --
 -- returns:
 --   tree.Node - the marshaled tree.Node table.
-function M.marshal_line(line)
-    -- number of characters up to the expand symbol encode
-    -- the node's tree depth.
-    local depth  = vim.fn.match(line, "[▼▶]")
-    if depth == -1 then
-        vim.api.nvim_err_writeln("failed to find matching character: " .. depth)
-        return
-    end
-
-    -- just your normal string parsing to carve out the symbol portion
-    -- of the line.
-    local symbol_and_type = vim.fn.strcharpart(line, depth+2)
-    local symbol_end_idx = vim.fn.stridx(symbol_and_type, "[")
-    local symbol = vim.fn.strpart(symbol_and_type, 0, symbol_end_idx)
-
-    for _, node in ipairs(tree.depth_table[depth]) do
-        if node.name == symbol then
-            return node
-        end
-    end
-    return nil
+function M.marshal_line(linenr)
+    local node = M.buf_line_map[linenr[1]]
+    return node
 end
 
 -- marshal_tree recursively marshals all nodes from the provided root
@@ -100,7 +86,12 @@ end
 -- node : tree.Node - the root node of the tree where marshaling will 
 -- begin.
 function M.marshal_tree(buf_handle, lines, node)
+    if node.depth == 0 then
+        -- create a new line mapping
+        buf_line_map = {}
+    end
     table.insert(lines, M.marshal_node(node))
+    M.buf_line_map[#lines] = node
 
     -- if we are an expanded node or we are the root (always expand)
     -- recurse