Feature: Source layout improvements

Historically, many Squid source files have been dumped into squid/src directory. That directory has accumulated more than 400 source files. This project will group closely related files and place groups in individual directories. The squid/src directory will contain pretty much nothing but Makefiles and subdirectories.

Squid Source Code Layout

This section is used to edit and finalize the grouping of source files. The Group column contains src/ subdirectory names. The Files section lists current file names and assumes file extensions .h, .cc, and .cci are added to the corresponding file names and masks.

Key:

  • (empty) - not even checked yet to see if this needs doing.

  • <:( in a sad state of affairs.

  • (./) Done.

  • :\ Improved, but needs more work. Nobody is working on this now. See the To-do column for details.

  • {1} AlexRousskov doing now.

  • {2} AmosJeffries doing now.

  • {3} FrancescoChemolli doing now.

Unit
Tests

Stub

Namespace

Polish

Group

Definition

Files and To-do

:\

-

-

:\

~/compat/

Portability primitives.
This is a full layer below everything, should be seamless with the OS API.

** migrate remaining pieces from squid.h and squid-old.h into compat

<:(

<:(

<:(

:\

acl/

Access Controls

ACL* external_acl.*, Add Acl namespace and rename classes?

<:(

<:(

<:(

(./)

adaptation/

code common to eCAP and ICAP

<:(

<:(

<:(

(./)

adaptation/ecap/

eCAP support

<:(

<:(

<:(

(./)

adaptation/icap/

ICAP support

<:(

<:(

(./)

(./)

anyp/

Protocol-independent protocol primitives

url* urn* ProtoPort*

<:(

<:(

:\

:\

auth/

Authentication support

rename classes into Auth namespace.

<:(

<:(

{X}

:\

base/

Commonly used code without a better place to go.

Async*? wordlist.* dlink.* hash.* string.* SquidString.*

<:(

<:(

:\

:\

comm/

I/O subsystem

<:(

<:(

<:(

config/

squid.conf parsing and management

cache_cf.* cf.* cf_* Parser.*

<:(

<:(

<:(

debug/

Debug core utilities

debug.cc Debug.h

<:(

<:(

<:(

:\

dns/

DNS components (Internal, dnsserver, caches)

dns*, ipcache.* fqdncache.*

<:(

<:(

<:(

:\

esi/

ESI support

ESI*, Add Esi namespace, rename classes

<:(

<:(

<:(

(./)

eui/

EUI-48 / MAC / ARP operations

<:(

<:(

(./)

:\ {2}

format/

Custom formatting

<:(

<:(

<:(

:\

fs/

file system-specific cache store support?

fs/*, Add Fs namespace, rename classes, add Makefiles for subdirs.

(./)

<:(

{3}

:\

fs/ufs

Ufs cache_dir

FrancescoChemolli. Fs::Ufs namespace, renamed files. TODO: rename classes

<:(

<:(

<:(

{2}

http/

HTTP primitives shared by client, server, and ICAP sides

Http*

<:(

<:(

<:(

:\

icmp/

ICMP support and Network measurement

Icmp* net_db.*, C++ convert net_db*, Add Icmp namespace and rename classes

<:(

<:(

<:(

:\

ident/

IDENT support

ident.* Make remote connection handling into an AsyncJob

<:(

<:(

(./)

(./)

ip/

IP Protocol

Ip* Qos*

<:(

<:(

<:(

:\

ipc/

inter-process communication

ipc.* ipc_win32.*, Move files, add Icp namespace to them, and adjust global names

<:(

<:(

<:(

{2}

log/

Logging components

namespace for Custom log formats and tokenizer. classify

<:(

<:(

<:(

mem/

Basic Memory management

mem*

<:(

<:(

<:(

:\

mgr/

Cache Manager

Move in CacheManager.h, cache_manager.cc, and test cases

<:(

<:(

<:(

redirect/

URL alteration (redirectors, URL-rewrite, URL maps)

redirect.* RedirectInternal.*

<:(

<:(

<:(

:\

repl/heap/

HEAP Replacement Policy algorithms

<:(

<:(

<:(

:\

repl/lru/

Cache Replacement Policy algorithms

<:(

<:(

<:(

:\

snmp/

SNMP components

snmp_*, move core and agent code. restructure for extensibility.

<:(

<:(

<:(

:\

ssl/

SSL components

ssl_* ssl.cc

<:(

<:(

<:(

shaping/

Traffic shaping and delay pools

*[Dd]elay.* *[Pp]ool*.*

<:(

<:(

<:(

store/

generic (fs-agnostic) disk and memory cache support?

Store* store*

<:(

<:(

<:(

time/

time and date handling tools

time.* squidTime.*

Non-Squid Bundled Source code

This section is used to edit and finalize the grouping of source files important for users but not integral to build and run Squid. These sources are generally contributed by third parties and vetted by the Squid Developers for bundling.

Directory

Content Type

helpers/

Helper applications which may be run by configuration.

basic_auth/

auth_param basic

digest_auth/

auth_param digest

external_acl/

external_acl_type

log_daemon/

logfile_daemon

negotiate_auth/

auth_param negotiate

ntlm_auth/

auth_param ntlm

url_rewrite/

URL re-writers (url_rewrite_program)

modules/

Extension modules which may be linked by configuration.

ecap/

eCAP

tools/

Administration tools

Problems

If you know the solution or can improve the proposed one, please write to squid-dev mailing list.

Problem

Proposed solution

Where to put OS-compatibilities wrappers that are currently located in squid/lib and squid/include?

squid/compat/ but due to auto-conf limitations the code must still be in .c files.

Where to put 3rd party libraries that are currently located in squid/lib and squid/include?

squid/import/libFoo/

Can we remove Foo prefix from FOO/FooSomething.h file names? The prefix carries no additional information and is probably not required for modern compilers, especially in C++ world.

Yes, Carefully
File name should match the primary class declared or defined in that file. Directory name should match the (lowercased) namespace used by classes in that directory. We should move from PROTOFoo to PROTO::Foo classes.

Ensure that there is no squid/src/Foo.h or squid/include/Foo.h file before using a foo/Foo.h. Some systemic problems have been found cleaning filenames like this with compiler include methods.

Should client- and server- side files be separated?

yes

Should directory names use just_small, CamelCase, or CAPS letters?

lower_case

Should class and file names use just_small, CamelCase, or CAPS letters?

CamelCaseHttpAcronymsIncluded

Should we use squid/src/squid/ root for most sources to include header files as <squid/group/file.h>? This may be required for installed headers and 3rd party code using those headers. It is not clear whether Squid will have installed headers in the foreseeable future. The Feature/eCAP work will determine that.

no

Should we form a generic mini-cache object type to combine the shared portions of fqdncache, ipcache, idns queue, netdb, ident-cache, maybe others not yet found?

Probably, that will be a separate feature event though.

What to do with all the mixed test* and stub_* files during this restructure?

Sticking them in the same folder as the code was a bad idea due to dependency linkages and dist order. For now sick them in tests/ folder. TODO: We should probably split the stubs into a stubs/ folder and remove the file prefixes.

Dependency Issues:

  • Cache manager storeAppendPrintf - just about every component uses this old function to dump it's stats to the cache manager output. It depends on StoreEntry which pulls in the entire store component tree. We need to make it use something something smaller.

    • An earlier attempt was made to use StoreEntryStream, but that still pulls in StoreEntry.

    • MemBuf is looking like a good all-purpose buffer we can have the components dump their text into. Which is then dumped into a StoreEntry by the cache manager

  • debugs() macro handling still has a small circular dependency with libsquid/libbase files and file IO.

  • automake can generate library dependency links for us from foo_LDADD. But most of the makefiles are using foo_DEPENDENCIES which disables that functionality. We should change to using EXTRA_foo_DEPENDENCIES instead and remove any objects duplicated with the foo_LDADD.

Other:

Explicit initialization vs self-initialization 

The more I think on this the more I am of the opinion that using
self-registering static/global objects as method of initialization &
registration is generally a mistake. Better if each such class have a
method for initialization, with initialization order explicitly coded in
the main program. Also makes transition to runtime loaded modules easier
and less intrusive as each module can assume the modules it registers
into has been properly initialized already which means it can do a full
initialization.

Regards
Henrik

CategoryFeature

Features/SourceLayout (last edited 2012-08-06 20:18:58 by FrancescoChemolli)