From 09dce08fd4d759bb76f5f646e55c83749b1cad14 Mon Sep 17 00:00:00 2001
From: Daniel Hahler <git@thequod.de>
Date: Wed, 29 Jul 2015 18:44:18 +0200
Subject: [PATCH] gears.debug: add support for limited depth
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This is useful with big tables and might even be necessary to prevent
infinite recursion.

To prevent the latter, the default is 10.

This adds an indicator when `depth` is reached for tables.

    awesome# return require("gears").debug.dump_return(t4, "", 2)
       string " : table: 0x1580130
      1 : table: 0x16951d0
        1 : wibox.widget.base (table) […]
        2 : wibox.widget.base (table) […]
        3 : 4 (number)
        4 : 5 (number)
        5 : foo (string)
      2 : table: 0x16ac790
        1 : table: 0x16951d0 (table) […]
      3 : table: 0x16cc500
        1 : table: 0x16951d0 (table) […]
        2 : table: 0x16ac790 (table) […]"

    awesome# return require("gears").debug.dump_return(t4, "", 1)
       string " : table: 0x1580130
      1 : table: 0x16951d0 (table) […]
      2 : table: 0x16ac790 (table) […]
      3 : table: 0x16cc500 (table) […]"

Closes https://github.com/awesomeWM/awesome/pull/372.
---
 lib/gears/debug.lua | 36 ++++++++++++++++++++++--------------
 1 file changed, 22 insertions(+), 14 deletions(-)

diff --git a/lib/gears/debug.lua b/lib/gears/debug.lua
index e1b7478f..9f56e839 100644
--- a/lib/gears/debug.lua
+++ b/lib/gears/debug.lua
@@ -26,27 +26,33 @@ function debug.assert(cond, message)
 end
 
 --- Given a table (or any other data) return a string that contains its
--- tag, value and type. If data is a table then recursively call d_raw
+-- tag, value and type. If data is a table then recursively call `dump_raw`
 -- on each of its values.
 -- @param data Value to inspect.
 -- @param shift Spaces to indent lines with.
 -- @param tag The name of the value.
+-- @tparam[opt=10] int depth Depth of recursion.
 -- @return a string which contains tag, value, value type and table key/value
 -- pairs if data is a table.
-local function dump_raw(data, shift, tag)
+local function dump_raw(data, shift, tag, depth)
+    depth = depth == nil and 10 or depth or 0
     local result = ""
 
     if tag then
         result = result .. tostring(tag) .. " : "
     end
 
-    if type(data) ~= "table" then
-        return result .. tostring(data) .. " (" .. type(data) .. ")"
-    end
-
-    shift = (shift or "") .. "  "
-    for k, v in pairs(data) do
-        result = result .. "\n" .. shift .. dump_raw(v, shift, k)
+    if type(data) == "table" and depth > 0 then
+        shift = (shift or "") .. "  "
+        result = result .. tostring(data)
+        for k, v in pairs(data) do
+            result = result .. "\n" .. shift .. dump_raw(v, shift, k, depth - 1)
+        end
+    else
+        result = result .. tostring(data) .. " (" .. type(data) .. ")"
+        if depth == 0 and type(data) == "table" then
+            result = result .. " […]"
+        end
     end
 
     return result
@@ -55,16 +61,18 @@ end
 --- Inspect the value in data.
 -- @param data Value to inspect.
 -- @param tag The name of the value.
--- @return a string that contains the expanded value of data.
-function debug.dump_return(data, tag)
-    return dump_raw(data, nil, tag)
+-- @tparam[opt] int depth Depth of recursion.
+-- @return string A string that contains the expanded value of data.
+function debug.dump_return(data, tag, depth)
+    return dump_raw(data, nil, tag, depth)
 end
 
 --- Print the table (or any other value) to the console.
 -- @param data Table to print.
 -- @param tag The name of the table.
-function debug.dump(data, tag)
-    print(debug.dump_return(data, tag))
+-- @tparam[opt] int depth Depth of recursion.
+function debug.dump(data, tag, depth)
+    print(debug.dump_return(data, tag, depth))
 end
 
 return debug