tools.get_tool_flags(): Return vector of flags instead of string

Adds a parser so users don't have to change their e2.conf. The parser
handles single and double quote strings as well as \\ and \" escapes.

Allows converting all tool calls to argv without loss of functionality.

Signed-off-by: Tobias Ulmer <tu@emlix.com>

diff --git a/generic/tools.lua b/generic/tools.lua
index e733cbda1fdb23d6ca5451123acf9ecef0a6c8fb..7b20c3c7b4e490c641fd7ff402a0ac8ec064ddd2 100644 (file)
--- a/generic/tools.lua
+++ b/generic/tools.lua
@@ -71,15 +71,94 @@ function tools.get_tool(name)
     return toollist[name].path
 end
 
+--- Split tool flags into a vector of arguments.
+-- @param flags Tool flags.
+-- @return Vector containing tool arguments or false on error.
+-- @return Error object on failure.
+local function parse_tool_flags(flags)
+    local tokens, c, fields, field, state, esc
+
+    state = 0 -- 0 default, 1 doublequote, 2 singlequote string
+    esc = false -- previous character was a escape \ if true
+    field = ""
+    fields = {}
+
+    for i=1,string.len(flags) do
+        c = string.sub(flags, i, i)
+        if state == 0 and (c == " " or c == "\t" or c == "\n") then
+            if field ~= "" then
+                table.insert(fields, field)
+                field = ""
+            end
+            -- skip all IFS
+        elseif c == '\\' then
+            esc = true
+            -- may add \ back later
+        elseif not esc and c == '"' and (state == 0 or state == 1) then
+            if state == 1 then
+                state = 0
+            else
+                state = 1
+            end
+            -- double quotes get removed
+        elseif c == "'" and (state == 0 or state == 2) then
+            if state == 2 then
+                state = 0
+            else
+                state = 2
+            end
+            -- single quotes get removed
+        else
+            if esc and (state == 0 or state == 1) then
+                if c == "\\" then
+                    field = field .. "\\"
+                elseif c == '"' then
+                    field = field .. '"'
+                elseif c == "'" then
+                    field = field .. "'"
+                else
+                    field = field .. "\\" .. c
+                end
+                esc = false
+            elseif esc and state == 2 then
+                -- no escape from the single quote
+                field = field .. "\\" .. c
+                esc = false
+            else
+                field = field .. c
+            end
+        end
+    end
+
+    if field ~= "" then
+        table.insert(fields, field)
+    end
+
+    if state ~= 0 or esc ~= false then
+        return false,
+            err.new("escape or quoting missmatch in tool flags %q", flags)
+    end
+
+    return fields
+end
+
 --- Get tool flags.
 -- @param name Tool name (string).
--- @return Tool flags as a string, potentially empty - or false on error.
+-- @return Vector containing tool flags. Vector may be empty for no flags,
+--         or false if an error occured.
 -- @return Error object on failure.
 function tools.get_tool_flags(name)
+    local flags, re
     if not toollist[name] then
         return false, err.new("tool '%s' is not registered in tool list", name)
     end
-    return toollist[name].flags or ""
+
+    flags, re = parse_tool_flags(toollist[name].flags or "")
+    if not flags then
+        return false, re
+    end
+
+    return flags
 end
 
 --- Get tool name.