Rework the devshell

From: Chris Larson <[email protected]>

- Adds a utility metaclass for maintaining class registries
- Shifts the handling of spawning a terminal into a new 'terminal' python module
- Automatically selects an appropriate terminal based on what you have available on your machine
- Still allows manual selection, but in a more convenient way, and falls back to auto if you select an invalid or unavailable (not installed) terminal
- Improves how we spawn screen:

- Shows a warning when spawning it, so do_devshell doesn't appear to hang
- Spawns a named screen session 'devshell', to avoid confusion when the user already has other screen sessions running

Pull URL: https://github.com/kergoth/oe-core
Branch: devshell
Browse: https://github.com/kergoth/oe-core/commits/devshell

Thanks,
Chris Larson <[email protected]>
---

Chris Larson (3):
oe.classutils: add module
Rework how the devshell functions
oe.terminal: improve how we spawn screen

 meta/classes/devshell.bbclass |   26 ++++-------
 meta/lib/oe/classutils.py     |   24 +++++++++
 meta/lib/oe/terminal.py       |  105 +++++++++++++++++++++++++++++++++++++++++
 3 files changed, 138 insertions(+), 17 deletions(-)
 create mode 100644 meta/lib/oe/classutils.py
 create mode 100644 meta/lib/oe/terminal.py

1.7.4.1

From: Chris Larson <[email protected]>

This adds a ClassRegistry utility metaclass, as maintaining a class registry is a fairly common thing to do.

---
 meta/lib/oe/classutils.py |   24 ++++++++++++++++++++++++
 1 files changed, 24 insertions(+), 0 deletions(-)
 create mode 100644 meta/lib/oe/classutils.py

new file mode 100644
index 0000000..855d2fa
@@ -0,0 +1,24 @@
+class ClassRegistry(type):
+    """Maintain a registry of classes, indexed by name.
+
+    The name in the registry can be overridden via the 'name' attribute of the
+    class, and the 'priority' attribute controls priority.  The prioritized()
+    method returns the registered classes in priority order."""
+    registry = {}
+    priority = 0
+
+    def __init__(cls, name, bases, attrs):
+        super(ClassRegistry, cls).__init__(name, bases, attrs)
+        if not hasattr(cls, name):
+            cls.name = name
+        cls.registry[cls.name] = cls
+
+    @classmethod
+    def prioritized(tcls):
+        return sorted(tcls.registry.values(),
+                      key=lambda v: v.priority, reverse=True)
+
+    def unregister(cls):
+        for key in cls.registry.keys():
+            if cls.registry[key] is cls:
+                del cls.registry[key]

1.7.4.1

From: Chris Larson <[email protected]>

In the new implementation, each known terminal is defined as a class in oe.terminal, as a subclass of bb.process.Popen. terminal.bbclass wraps this functionality, providing the metadata pieces. It obeys the OE_TERMINAL variable, which is a 'choice' typed variable. This variable may be 'auto', 'none', or any of the names of the defined terminals.

When using 'auto', or requesting an unsupported terminal, we attempt to spawn them in priority order until we get one that's available on this system (and in the case of the X terminals, has DISPLAY defined). The 'none' value is used when we're doing things like automated builds, and want to ensure that no terminal is *ever* spawned, under any circumstances.

Current available terminals:

gnome
konsole
xterm
rxvt
screen

---
 meta/classes/devshell.bbclass |   26 ++++-------
 meta/lib/oe/terminal.py       |  100 +++++++++++++++++++++++++++++++++++++++++
 2 files changed, 109 insertions(+), 17 deletions(-)
 create mode 100644 meta/lib/oe/terminal.py

index 5f262f4..7317d64 100644
@@ -1,22 +1,14 @@
-do_devshell[dirs] = "${S}"
-do_devshell[nostamp] = "1"
+inherit terminal
 
-XAUTHORITY ?= "${HOME}/.Xauthority"
 
-devshell_do_devshell() {
-	export DISPLAY='${DISPLAY}'
-	export DBUS_SESSION_BUS_ADDRESS='${DBUS_SESSION_BUS_ADDRESS}'
-	export XAUTHORITY='${XAUTHORITY}'
-	export TERMWINDOWTITLE="Bitbake Developer Shell"
-	export EXTRA_OEMAKE='${EXTRA_OEMAKE}'
-	export SHELLCMDS="bash"
-	${TERMCMDRUN}
-	if [ $? -ne 0 ]; then
-	    echo "Fatal: '${TERMCMD}' not found. Check TERMCMD variable."
-	    exit 1
-	fi
+export XAUTHORITY ?= "${HOME}/.Xauthority"
+export SHELL ?= 'bash'
+
+python do_devshell () {
+    oe_terminal(d.getVar('SHELL', True), 'OpenEmbedded Developer Shell', d)
 }
-addtask devshell after do_patch
 
-EXPORT_FUNCTIONS do_devshell
+addtask devshell after do_patch
 
+do_devshell[dirs] = "${S}"
+do_devshell[nostamp] = "1"

1.7.4.1

From: Chris Larson <[email protected]>

- Name the screen session 'devshell', to avoid confusion if running bitbake itself under a screen session.
- Display a warning message when spawning screen, so it's clear to the user that screen has been run (otherwise do_devshell just appears to hang).

---
 meta/lib/oe/terminal.py |    7 ++++++-
 1 files changed, 6 insertions(+), 1 deletions(-)

index 8c8e5b2..a94b113 100644
@@ -68,7 +68,12 @@ class Rxvt(XTerminal):
     priority = 1
 
 class Screen(Terminal):
-    cmd = 'screen -D -m -t "{title}" {cmd}'
+    cmd = 'screen -D -m -t "{title}" -S devshell {cmd}'
+
+    def __init__(self, cmd, title=None):
+        logger.warn('Screen started. Please connect in another terminal with '
+                    '"screen -r devshell"')
+        Terminal.__init__(self, cmd, title)
 
 
 def prioritized():

1.7.4.1

Note: this depends on the variable typing from the previous pull request, forgot to add that to the cover letter.

Christopher Larson
clarson at kergoth dot com
Founder - BitBake, OpenEmbedded, OpenZaurus
Maintainer - Tslib
Senior Software Engineer, Mentor Graphics

Er, ignore this pull request, a v2 will be forthcoming (missed a file).

Christopher Larson
clarson at kergoth dot com
Founder - BitBake, OpenEmbedded, OpenZaurus
Maintainer - Tslib
Senior Software Engineer, Mentor Graphics