contrib / hooks / post-receive-emailon commit Merge branch 'sb/mailmap-updates' (4fcd30d)
   1#!/bin/sh
   2#
   3# Copyright (c) 2007 Andy Parkins
   4#
   5# An example hook script to mail out commit update information.
   6#
   7# NOTE: This script is no longer under active development.  There
   8# is another script, git-multimail, which is more capable and
   9# configurable and is largely backwards-compatible with this script;
  10# please see "contrib/hooks/multimail/".  For instructions on how to
  11# migrate from post-receive-email to git-multimail, please see
  12# "README.migrate-from-post-receive-email" in that directory.
  13#
  14# This hook sends emails listing new revisions to the repository
  15# introduced by the change being reported.  The rule is that (for
  16# branch updates) each commit will appear on one email and one email
  17# only.
  18#
  19# This hook is stored in the contrib/hooks directory.  Your distribution
  20# will have put this somewhere standard.  You should make this script
  21# executable then link to it in the repository you would like to use it in.
  22# For example, on debian the hook is stored in
  23# /usr/share/git-core/contrib/hooks/post-receive-email:
  24#
  25#  chmod a+x post-receive-email
  26#  cd /path/to/your/repository.git
  27#  ln -sf /usr/share/git-core/contrib/hooks/post-receive-email hooks/post-receive
  28#
  29# This hook script assumes it is enabled on the central repository of a
  30# project, with all users pushing only to it and not between each other.  It
  31# will still work if you don't operate in that style, but it would become
  32# possible for the email to be from someone other than the person doing the
  33# push.
  34#
  35# To help with debugging and use on pre-v1.5.1 git servers, this script will
  36# also obey the interface of hooks/update, taking its arguments on the
  37# command line.  Unfortunately, hooks/update is called once for each ref.
  38# To avoid firing one email per ref, this script just prints its output to
  39# the screen when used in this mode.  The output can then be redirected if
  40# wanted.
  41#
  42# Config
  43# ------
  44# hooks.mailinglist
  45#   This is the list that all pushes will go to; leave it blank to not send
  46#   emails for every ref update.
  47# hooks.announcelist
  48#   This is the list that all pushes of annotated tags will go to.  Leave it
  49#   blank to default to the mailinglist field.  The announce emails lists
  50#   the short log summary of the changes since the last annotated tag.
  51# hooks.envelopesender
  52#   If set then the -f option is passed to sendmail to allow the envelope
  53#   sender address to be set
  54# hooks.emailprefix
  55#   All emails have their subjects prefixed with this prefix, or "[SCM]"
  56#   if emailprefix is unset, to aid filtering
  57# hooks.showrev
  58#   The shell command used to format each revision in the email, with
  59#   "%s" replaced with the commit id.  Defaults to "git rev-list -1
  60#   --pretty %s", displaying the commit id, author, date and log
  61#   message.  To list full patches separated by a blank line, you
  62#   could set this to "git show -C %s; echo".
  63#   To list a gitweb/cgit URL *and* a full patch for each change set, use this:
  64#     "t=%s; printf 'http://.../?id=%%s' \$t; echo;echo; git show -C \$t; echo"
  65#   Be careful if "..." contains things that will be expanded by shell "eval"
  66#   or printf.
  67# hooks.emailmaxlines
  68#   The maximum number of lines that should be included in the generated
  69#   email body. If not specified, there is no limit.
  70#   Lines beyond the limit are suppressed and counted, and a final
  71#   line is added indicating the number of suppressed lines.
  72# hooks.diffopts
  73#   Alternate options for the git diff-tree invocation that shows changes.
  74#   Default is "--stat --summary --find-copies-harder". Add -p to those
  75#   options to include a unified diff of changes in addition to the usual
  76#   summary output.
  77#
  78# Notes
  79# -----
  80# All emails include the headers "X-Git-Refname", "X-Git-Oldrev",
  81# "X-Git-Newrev", and "X-Git-Reftype" to enable fine tuned filtering and
  82# give information for debugging.
  83#
  84
  85# ---------------------------- Functions
  86
  87#
  88# Function to prepare for email generation. This decides what type
  89# of update this is and whether an email should even be generated.
  90#
  91prep_for_email()
  92{
  93        # --- Arguments
  94        oldrev=$(git rev-parse $1)
  95        newrev=$(git rev-parse $2)
  96        refname="$3"
  97
  98        # --- Interpret
  99        # 0000->1234 (create)
 100        # 1234->2345 (update)
 101        # 2345->0000 (delete)
 102        if expr "$oldrev" : '0*$' >/dev/null
 103        then
 104                change_type="create"
 105        else
 106                if expr "$newrev" : '0*$' >/dev/null
 107                then
 108                        change_type="delete"
 109                else
 110                        change_type="update"
 111                fi
 112        fi
 113
 114        # --- Get the revision types
 115        newrev_type=$(git cat-file -t $newrev 2> /dev/null)
 116        oldrev_type=$(git cat-file -t "$oldrev" 2> /dev/null)
 117        case "$change_type" in
 118        create|update)
 119                rev="$newrev"
 120                rev_type="$newrev_type"
 121                ;;
 122        delete)
 123                rev="$oldrev"
 124                rev_type="$oldrev_type"
 125                ;;
 126        esac
 127
 128        # The revision type tells us what type the commit is, combined with
 129        # the location of the ref we can decide between
 130        #  - working branch
 131        #  - tracking branch
 132        #  - unannoted tag
 133        #  - annotated tag
 134        case "$refname","$rev_type" in
 135                refs/tags/*,commit)
 136                        # un-annotated tag
 137                        refname_type="tag"
 138                        short_refname=${refname##refs/tags/}
 139                        ;;
 140                refs/tags/*,tag)
 141                        # annotated tag
 142                        refname_type="annotated tag"
 143                        short_refname=${refname##refs/tags/}
 144                        # change recipients
 145                        if [ -n "$announcerecipients" ]; then
 146                                recipients="$announcerecipients"
 147                        fi
 148                        ;;
 149                refs/heads/*,commit)
 150                        # branch
 151                        refname_type="branch"
 152                        short_refname=${refname##refs/heads/}
 153                        ;;
 154                refs/remotes/*,commit)
 155                        # tracking branch
 156                        refname_type="tracking branch"
 157                        short_refname=${refname##refs/remotes/}
 158                        echo >&2 "*** Push-update of tracking branch, $refname"
 159                        echo >&2 "***  - no email generated."
 160                        return 1
 161                        ;;
 162                *)
 163                        # Anything else (is there anything else?)
 164                        echo >&2 "*** Unknown type of update to $refname ($rev_type)"
 165                        echo >&2 "***  - no email generated"
 166                        return 1
 167                        ;;
 168        esac
 169
 170        # Check if we've got anyone to send to
 171        if [ -z "$recipients" ]; then
 172                case "$refname_type" in
 173                        "annotated tag")
 174                                config_name="hooks.announcelist"
 175                                ;;
 176                        *)
 177                                config_name="hooks.mailinglist"
 178                                ;;
 179                esac
 180                echo >&2 "*** $config_name is not set so no email will be sent"
 181                echo >&2 "*** for $refname update $oldrev->$newrev"
 182                return 1
 183        fi
 184
 185        return 0
 186}
 187
 188#
 189# Top level email generation function.  This calls the appropriate
 190# body-generation routine after outputting the common header.
 191#
 192# Note this function doesn't actually generate any email output, that is
 193# taken care of by the functions it calls:
 194#  - generate_email_header
 195#  - generate_create_XXXX_email
 196#  - generate_update_XXXX_email
 197#  - generate_delete_XXXX_email
 198#  - generate_email_footer
 199#
 200# Note also that this function cannot 'exit' from the script; when this
 201# function is running (in hook script mode), the send_mail() function
 202# is already executing in another process, connected via a pipe, and
 203# if this function exits without, whatever has been generated to that
 204# point will be sent as an email... even if nothing has been generated.
 205#
 206generate_email()
 207{
 208        # Email parameters
 209        # The email subject will contain the best description of the ref
 210        # that we can build from the parameters
 211        describe=$(git describe $rev 2>/dev/null)
 212        if [ -z "$describe" ]; then
 213                describe=$rev
 214        fi
 215
 216        generate_email_header
 217
 218        # Call the correct body generation function
 219        fn_name=general
 220        case "$refname_type" in
 221        "tracking branch"|branch)
 222                fn_name=branch
 223                ;;
 224        "annotated tag")
 225                fn_name=atag
 226                ;;
 227        esac
 228
 229        if [ -z "$maxlines" ]; then
 230                generate_${change_type}_${fn_name}_email
 231        else
 232                generate_${change_type}_${fn_name}_email | limit_lines $maxlines
 233        fi
 234
 235        generate_email_footer
 236}
 237
 238generate_email_header()
 239{
 240        # --- Email (all stdout will be the email)
 241        # Generate header
 242        cat <<-EOF
 243        To: $recipients
 244        Subject: ${emailprefix}$projectdesc $refname_type $short_refname ${change_type}d. $describe
 245        X-Git-Refname: $refname
 246        X-Git-Reftype: $refname_type
 247        X-Git-Oldrev: $oldrev
 248        X-Git-Newrev: $newrev
 249        Auto-Submitted: auto-generated
 250
 251        This is an automated email from the git hooks/post-receive script. It was
 252        generated because a ref change was pushed to the repository containing
 253        the project "$projectdesc".
 254
 255        The $refname_type, $short_refname has been ${change_type}d
 256        EOF
 257}
 258
 259generate_email_footer()
 260{
 261        SPACE=" "
 262        cat <<-EOF
 263
 264
 265        hooks/post-receive
 266        --${SPACE}
 267        $projectdesc
 268        EOF
 269}
 270
 271# --------------- Branches
 272
 273#
 274# Called for the creation of a branch
 275#
 276generate_create_branch_email()
 277{
 278        # This is a new branch and so oldrev is not valid
 279        echo "        at  $newrev ($newrev_type)"
 280        echo ""
 281
 282        echo $LOGBEGIN
 283        show_new_revisions
 284        echo $LOGEND
 285}
 286
 287#
 288# Called for the change of a pre-existing branch
 289#
 290generate_update_branch_email()
 291{
 292        # Consider this:
 293        #   1 --- 2 --- O --- X --- 3 --- 4 --- N
 294        #
 295        # O is $oldrev for $refname
 296        # N is $newrev for $refname
 297        # X is a revision pointed to by some other ref, for which we may
 298        #   assume that an email has already been generated.
 299        # In this case we want to issue an email containing only revisions
 300        # 3, 4, and N.  Given (almost) by
 301        #
 302        #  git rev-list N ^O --not --all
 303        #
 304        # The reason for the "almost", is that the "--not --all" will take
 305        # precedence over the "N", and effectively will translate to
 306        #
 307        #  git rev-list N ^O ^X ^N
 308        #
 309        # So, we need to build up the list more carefully.  git rev-parse
 310        # will generate a list of revs that may be fed into git rev-list.
 311        # We can get it to make the "--not --all" part and then filter out
 312        # the "^N" with:
 313        #
 314        #  git rev-parse --not --all | grep -v N
 315        #
 316        # Then, using the --stdin switch to git rev-list we have effectively
 317        # manufactured
 318        #
 319        #  git rev-list N ^O ^X
 320        #
 321        # This leaves a problem when someone else updates the repository
 322        # while this script is running.  Their new value of the ref we're
 323        # working on would be included in the "--not --all" output; and as
 324        # our $newrev would be an ancestor of that commit, it would exclude
 325        # all of our commits.  What we really want is to exclude the current
 326        # value of $refname from the --not list, rather than N itself.  So:
 327        #
 328        #  git rev-parse --not --all | grep -v $(git rev-parse $refname)
 329        #
 330        # Get's us to something pretty safe (apart from the small time
 331        # between refname being read, and git rev-parse running - for that,
 332        # I give up)
 333        #
 334        #
 335        # Next problem, consider this:
 336        #   * --- B --- * --- O ($oldrev)
 337        #          \
 338        #           * --- X --- * --- N ($newrev)
 339        #
 340        # That is to say, there is no guarantee that oldrev is a strict
 341        # subset of newrev (it would have required a --force, but that's
 342        # allowed).  So, we can't simply say rev-list $oldrev..$newrev.
 343        # Instead we find the common base of the two revs and list from
 344        # there.
 345        #
 346        # As above, we need to take into account the presence of X; if
 347        # another branch is already in the repository and points at some of
 348        # the revisions that we are about to output - we don't want them.
 349        # The solution is as before: git rev-parse output filtered.
 350        #
 351        # Finally, tags: 1 --- 2 --- O --- T --- 3 --- 4 --- N
 352        #
 353        # Tags pushed into the repository generate nice shortlog emails that
 354        # summarise the commits between them and the previous tag.  However,
 355        # those emails don't include the full commit messages that we output
 356        # for a branch update.  Therefore we still want to output revisions
 357        # that have been output on a tag email.
 358        #
 359        # Luckily, git rev-parse includes just the tool.  Instead of using
 360        # "--all" we use "--branches"; this has the added benefit that
 361        # "remotes/" will be ignored as well.
 362
 363        # List all of the revisions that were removed by this update, in a
 364        # fast-forward update, this list will be empty, because rev-list O
 365        # ^N is empty.  For a non-fast-forward, O ^N is the list of removed
 366        # revisions
 367        fast_forward=""
 368        rev=""
 369        for rev in $(git rev-list $newrev..$oldrev)
 370        do
 371                revtype=$(git cat-file -t "$rev")
 372                echo "  discards  $rev ($revtype)"
 373        done
 374        if [ -z "$rev" ]; then
 375                fast_forward=1
 376        fi
 377
 378        # List all the revisions from baserev to newrev in a kind of
 379        # "table-of-contents"; note this list can include revisions that
 380        # have already had notification emails and is present to show the
 381        # full detail of the change from rolling back the old revision to
 382        # the base revision and then forward to the new revision
 383        for rev in $(git rev-list $oldrev..$newrev)
 384        do
 385                revtype=$(git cat-file -t "$rev")
 386                echo "       via  $rev ($revtype)"
 387        done
 388
 389        if [ "$fast_forward" ]; then
 390                echo "      from  $oldrev ($oldrev_type)"
 391        else
 392                #  1. Existing revisions were removed.  In this case newrev
 393                #     is a subset of oldrev - this is the reverse of a
 394                #     fast-forward, a rewind
 395                #  2. New revisions were added on top of an old revision,
 396                #     this is a rewind and addition.
 397
 398                # (1) certainly happened, (2) possibly.  When (2) hasn't
 399                # happened, we set a flag to indicate that no log printout
 400                # is required.
 401
 402                echo ""
 403
 404                # Find the common ancestor of the old and new revisions and
 405                # compare it with newrev
 406                baserev=$(git merge-base $oldrev $newrev)
 407                rewind_only=""
 408                if [ "$baserev" = "$newrev" ]; then
 409                        echo "This update discarded existing revisions and left the branch pointing at"
 410                        echo "a previous point in the repository history."
 411                        echo ""
 412                        echo " * -- * -- N ($newrev)"
 413                        echo "            \\"
 414                        echo "             O -- O -- O ($oldrev)"
 415                        echo ""
 416                        echo "The removed revisions are not necessarily gone - if another reference"
 417                        echo "still refers to them they will stay in the repository."
 418                        rewind_only=1
 419                else
 420                        echo "This update added new revisions after undoing existing revisions.  That is"
 421                        echo "to say, the old revision is not a strict subset of the new revision.  This"
 422                        echo "situation occurs when you --force push a change and generate a repository"
 423                        echo "containing something like this:"
 424                        echo ""
 425                        echo " * -- * -- B -- O -- O -- O ($oldrev)"
 426                        echo "            \\"
 427                        echo "             N -- N -- N ($newrev)"
 428                        echo ""
 429                        echo "When this happens we assume that you've already had alert emails for all"
 430                        echo "of the O revisions, and so we here report only the revisions in the N"
 431                        echo "branch from the common base, B."
 432                fi
 433        fi
 434
 435        echo ""
 436        if [ -z "$rewind_only" ]; then
 437                echo "Those revisions listed above that are new to this repository have"
 438                echo "not appeared on any other notification email; so we list those"
 439                echo "revisions in full, below."
 440
 441                echo ""
 442                echo $LOGBEGIN
 443                show_new_revisions
 444
 445                # XXX: Need a way of detecting whether git rev-list actually
 446                # outputted anything, so that we can issue a "no new
 447                # revisions added by this update" message
 448
 449                echo $LOGEND
 450        else
 451                echo "No new revisions were added by this update."
 452        fi
 453
 454        # The diffstat is shown from the old revision to the new revision.
 455        # This is to show the truth of what happened in this change.
 456        # There's no point showing the stat from the base to the new
 457        # revision because the base is effectively a random revision at this
 458        # point - the user will be interested in what this revision changed
 459        # - including the undoing of previous revisions in the case of
 460        # non-fast-forward updates.
 461        echo ""
 462        echo "Summary of changes:"
 463        git diff-tree $diffopts $oldrev..$newrev
 464}
 465
 466#
 467# Called for the deletion of a branch
 468#
 469generate_delete_branch_email()
 470{
 471        echo "       was  $oldrev"
 472        echo ""
 473        echo $LOGBEGIN
 474        git show -s --pretty=oneline $oldrev
 475        echo $LOGEND
 476}
 477
 478# --------------- Annotated tags
 479
 480#
 481# Called for the creation of an annotated tag
 482#
 483generate_create_atag_email()
 484{
 485        echo "        at  $newrev ($newrev_type)"
 486
 487        generate_atag_email
 488}
 489
 490#
 491# Called for the update of an annotated tag (this is probably a rare event
 492# and may not even be allowed)
 493#
 494generate_update_atag_email()
 495{
 496        echo "        to  $newrev ($newrev_type)"
 497        echo "      from  $oldrev (which is now obsolete)"
 498
 499        generate_atag_email
 500}
 501
 502#
 503# Called when an annotated tag is created or changed
 504#
 505generate_atag_email()
 506{
 507        # Use git for-each-ref to pull out the individual fields from the
 508        # tag
 509        eval $(git for-each-ref --shell --format='
 510        tagobject=%(*objectname)
 511        tagtype=%(*objecttype)
 512        tagger=%(taggername)
 513        tagged=%(taggerdate)' $refname
 514        )
 515
 516        echo "   tagging  $tagobject ($tagtype)"
 517        case "$tagtype" in
 518        commit)
 519
 520                # If the tagged object is a commit, then we assume this is a
 521                # release, and so we calculate which tag this tag is
 522                # replacing
 523                prevtag=$(git describe --abbrev=0 $newrev^ 2>/dev/null)
 524
 525                if [ -n "$prevtag" ]; then
 526                        echo "  replaces  $prevtag"
 527                fi
 528                ;;
 529        *)
 530                echo "    length  $(git cat-file -s $tagobject) bytes"
 531                ;;
 532        esac
 533        echo " tagged by  $tagger"
 534        echo "        on  $tagged"
 535
 536        echo ""
 537        echo $LOGBEGIN
 538
 539        # Show the content of the tag message; this might contain a change
 540        # log or release notes so is worth displaying.
 541        git cat-file tag $newrev | sed -e '1,/^$/d'
 542
 543        echo ""
 544        case "$tagtype" in
 545        commit)
 546                # Only commit tags make sense to have rev-list operations
 547                # performed on them
 548                if [ -n "$prevtag" ]; then
 549                        # Show changes since the previous release
 550                        git rev-list --pretty=short "$prevtag..$newrev" | git shortlog
 551                else
 552                        # No previous tag, show all the changes since time
 553                        # began
 554                        git rev-list --pretty=short $newrev | git shortlog
 555                fi
 556                ;;
 557        *)
 558                # XXX: Is there anything useful we can do for non-commit
 559                # objects?
 560                ;;
 561        esac
 562
 563        echo $LOGEND
 564}
 565
 566#
 567# Called for the deletion of an annotated tag
 568#
 569generate_delete_atag_email()
 570{
 571        echo "       was  $oldrev"
 572        echo ""
 573        echo $LOGBEGIN
 574        git show -s --pretty=oneline $oldrev
 575        echo $LOGEND
 576}
 577
 578# --------------- General references
 579
 580#
 581# Called when any other type of reference is created (most likely a
 582# non-annotated tag)
 583#
 584generate_create_general_email()
 585{
 586        echo "        at  $newrev ($newrev_type)"
 587
 588        generate_general_email
 589}
 590
 591#
 592# Called when any other type of reference is updated (most likely a
 593# non-annotated tag)
 594#
 595generate_update_general_email()
 596{
 597        echo "        to  $newrev ($newrev_type)"
 598        echo "      from  $oldrev"
 599
 600        generate_general_email
 601}
 602
 603#
 604# Called for creation or update of any other type of reference
 605#
 606generate_general_email()
 607{
 608        # Unannotated tags are more about marking a point than releasing a
 609        # version; therefore we don't do the shortlog summary that we do for
 610        # annotated tags above - we simply show that the point has been
 611        # marked, and print the log message for the marked point for
 612        # reference purposes
 613        #
 614        # Note this section also catches any other reference type (although
 615        # there aren't any) and deals with them in the same way.
 616
 617        echo ""
 618        if [ "$newrev_type" = "commit" ]; then
 619                echo $LOGBEGIN
 620                git show --no-color --root -s --pretty=medium $newrev
 621                echo $LOGEND
 622        else
 623                # What can we do here?  The tag marks an object that is not
 624                # a commit, so there is no log for us to display.  It's
 625                # probably not wise to output git cat-file as it could be a
 626                # binary blob.  We'll just say how big it is
 627                echo "$newrev is a $newrev_type, and is $(git cat-file -s $newrev) bytes long."
 628        fi
 629}
 630
 631#
 632# Called for the deletion of any other type of reference
 633#
 634generate_delete_general_email()
 635{
 636        echo "       was  $oldrev"
 637        echo ""
 638        echo $LOGBEGIN
 639        git show -s --pretty=oneline $oldrev
 640        echo $LOGEND
 641}
 642
 643
 644# --------------- Miscellaneous utilities
 645
 646#
 647# Show new revisions as the user would like to see them in the email.
 648#
 649show_new_revisions()
 650{
 651        # This shows all log entries that are not already covered by
 652        # another ref - i.e. commits that are now accessible from this
 653        # ref that were previously not accessible
 654        # (see generate_update_branch_email for the explanation of this
 655        # command)
 656
 657        # Revision range passed to rev-list differs for new vs. updated
 658        # branches.
 659        if [ "$change_type" = create ]
 660        then
 661                # Show all revisions exclusive to this (new) branch.
 662                revspec=$newrev
 663        else
 664                # Branch update; show revisions not part of $oldrev.
 665                revspec=$oldrev..$newrev
 666        fi
 667
 668        other_branches=$(git for-each-ref --format='%(refname)' refs/heads/ |
 669            grep -F -v $refname)
 670        git rev-parse --not $other_branches |
 671        if [ -z "$custom_showrev" ]
 672        then
 673                git rev-list --pretty --stdin $revspec
 674        else
 675                git rev-list --stdin $revspec |
 676                while read onerev
 677                do
 678                        eval $(printf "$custom_showrev" $onerev)
 679                done
 680        fi
 681}
 682
 683
 684limit_lines()
 685{
 686        lines=0
 687        skipped=0
 688        while IFS="" read -r line; do
 689                lines=$((lines + 1))
 690                if [ $lines -gt $1 ]; then
 691                        skipped=$((skipped + 1))
 692                else
 693                        printf "%s\n" "$line"
 694                fi
 695        done
 696        if [ $skipped -ne 0 ]; then
 697                echo "... $skipped lines suppressed ..."
 698        fi
 699}
 700
 701
 702send_mail()
 703{
 704        if [ -n "$envelopesender" ]; then
 705                /usr/sbin/sendmail -t -f "$envelopesender"
 706        else
 707                /usr/sbin/sendmail -t
 708        fi
 709}
 710
 711# ---------------------------- main()
 712
 713# --- Constants
 714LOGBEGIN="- Log -----------------------------------------------------------------"
 715LOGEND="-----------------------------------------------------------------------"
 716
 717# --- Config
 718# Set GIT_DIR either from the working directory, or from the environment
 719# variable.
 720GIT_DIR=$(git rev-parse --git-dir 2>/dev/null)
 721if [ -z "$GIT_DIR" ]; then
 722        echo >&2 "fatal: post-receive: GIT_DIR not set"
 723        exit 1
 724fi
 725
 726projectdesc=$(sed -ne '1p' "$GIT_DIR/description" 2>/dev/null)
 727# Check if the description is unchanged from it's default, and shorten it to
 728# a more manageable length if it is
 729if expr "$projectdesc" : "Unnamed repository.*$" >/dev/null
 730then
 731        projectdesc="UNNAMED PROJECT"
 732fi
 733
 734recipients=$(git config hooks.mailinglist)
 735announcerecipients=$(git config hooks.announcelist)
 736envelopesender=$(git config hooks.envelopesender)
 737emailprefix=$(git config hooks.emailprefix || echo '[SCM] ')
 738custom_showrev=$(git config hooks.showrev)
 739maxlines=$(git config hooks.emailmaxlines)
 740diffopts=$(git config hooks.diffopts)
 741: ${diffopts:="--stat --summary --find-copies-harder"}
 742
 743# --- Main loop
 744# Allow dual mode: run from the command line just like the update hook, or
 745# if no arguments are given then run as a hook script
 746if [ -n "$1" -a -n "$2" -a -n "$3" ]; then
 747        # Output to the terminal in command line mode - if someone wanted to
 748        # resend an email; they could redirect the output to sendmail
 749        # themselves
 750        prep_for_email $2 $3 $1 && PAGER= generate_email
 751else
 752        while read oldrev newrev refname
 753        do
 754                prep_for_email $oldrev $newrev $refname || continue
 755                generate_email $maxlines | send_mail
 756        done
 757fi