Implement --lazy, --upgrade, --upgrade-deps, --reinstall-deps

Only for the install command for now.

src/luarocks/install.lua

@@ -22,6 +22,12 @@ install.help = [[
 Argument may be the name of a rock to be fetched from a repository
 or a filename of a locally available rock.
 
+--lazy              Do not install a rock by name if it's
+                    already installed.
+--upgrade           Do not install a rock by name if its
+                    latest version is already installed.
+--upgrade-deps      Recursively upgrade dependencies of the rock.
+--reinstall-deps    Recursively reinstall dependencies of the rock.
 --keep              Do not remove previously installed versions of the
                     rock after installing a new one. This behavior can
                     be made permanent by setting keep_other_versions=true
@@ -270,6 +276,18 @@ function install.run(...)
    local ok, err = fs.check_command_permissions(flags)
    if not ok then return nil, err, cfg.errorcodes.PERMISSIONDENIED end
 
+   if flags.upgrade then
+      flags.install_mode = "upgrade"
+   elseif flags.lazy then
+      flags.install_mode = "satisfy"
+   end
+
+   if flags["upgrade-deps"] then
+      flags.deps_install_mode = "upgrade"
+   elseif flags["reinstall-deps"] then
+      flags.deps_install_mode = "install"
+   end
+
    if name:match("%.rockspec$") or name:match("%.src%.rock$") or name:match("%.rock") then
       return install.install_by_url(name, flags)
    else

src/luarocks/util.lua

@@ -87,6 +87,7 @@ local supported_flags = {
    ["home"] = true,
    ["homepage"] = "\"<url>\"",
    ["keep"] = true,
+   ["lazy"] = true,
    ["lib"] = "<library>",
    ["license"] = "\"<text>\"",
    ["list"] = true,
@@ -114,6 +115,7 @@ local supported_flags = {
    ["pack-binary-rock"] = true,
    ["porcelain"] = true,
    ["quick"] = true,
+   ["reinstall-deps"] = true,
    ["rock-dir"] = true,
    ["rock-tree"] = true,
    ["rock-trees"] = true,
@@ -128,6 +130,8 @@ local supported_flags = {
    ["timeout"] = "<seconds>",
    ["to"] = "<path>",
    ["tree"] = "<path>",
+   ["upgrade"] = true,
+   ["upgrade-deps"] = true,
    ["user-config"] = true,
    ["verbose"] = true,
    ["version"] = true,