git-gui: Add support for calling out to the prepare-commit-msg hook

Signed-off-by: Joshua Williams <joshua.williams@qlogic.com>
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

diff --git a/git-gui.sh b/git-gui.sh
index 1939001..cb0fcac 100755 (executable)
--- a/git-gui.sh
+++ b/git-gui.sh
@@ -1170,6 +1170,7 @@ proc rescan {after {honor_trustmtime 1}} {
                || [string trim [$ui_comm get 0.0 end]] eq {})} {
                if {[string match amend* $commit_type]} {
                } elseif {[load_message GITGUI_MSG]} {
+               } elseif {[run_prepare_commit_msg_hook]} {
                } elseif {[load_message MERGE_MSG]} {
                } elseif {[load_message SQUASH_MSG]} {
                }
@@ -1269,6 +1270,70 @@ proc load_message {file} {
        return 0
 }
 
+proc run_prepare_commit_msg_hook {} {
+       global pch_error
+
+       # prepare-commit-msg requires PREPARE_COMMIT_MSG exist.  From git-gui
+       # it will be .git/MERGE_MSG (merge), .git/SQUASH_MSG (squash), or an
+       # empty file but existant file.
+
+       set fd_pcm [open [gitdir PREPARE_COMMIT_MSG] a]
+
+       if {[file isfile [gitdir MERGE_MSG]]} {
+               set pcm_source "merge"
+               set fd_mm [open [gitdir MERGE_MSG] r]
+               puts -nonewline $fd_pcm [read $fd_mm]
+               close $fd_mm
+       } elseif {[file isfile [gitdir SQUASH_MSG]]} {
+               set pcm_source "squash"
+               set fd_sm [open [gitdir SQUASH_MSG] r]
+               puts -nonewline $fd_pcm [read $fd_sm]
+               close $fd_sm
+       } else {
+               set pcm_source ""
+       }
+
+       close $fd_pcm
+
+       set fd_ph [githook_read prepare-commit-msg \
+                       [gitdir PREPARE_COMMIT_MSG] $pcm_source]
+       if {$fd_ph eq {}} {
+               catch {file delete [gitdir PREPARE_COMMIT_MSG]}
+               return 0;
+       }
+
+       ui_status [mc "Calling prepare-commit-msg hook..."]
+       set pch_error {}
+
+       fconfigure $fd_ph -blocking 0 -translation binary -eofchar {}
+       fileevent $fd_ph readable \
+               [list prepare_commit_msg_hook_wait $fd_ph]
+
+       return 1;
+}
+
+proc prepare_commit_msg_hook_wait {fd_ph} {
+       global pch_error
+
+       append pch_error [read $fd_ph]
+       fconfigure $fd_ph -blocking 1
+       if {[eof $fd_ph]} {
+               if {[catch {close $fd_ph}]} {
+                       ui_status [mc "Commit declined by prepare-commit-msg hook."]
+                       hook_failed_popup prepare-commit-msg $pch_error
+                       catch {file delete [gitdir PREPARE_COMMIT_MSG]}
+                       exit 1
+               } else {
+                       load_message PREPARE_COMMIT_MSG
+               }
+               set pch_error {}
+               catch {file delete [gitdir PREPARE_COMMIT_MSG]}
+               return
+        }
+       fconfigure $fd_ph -blocking 0
+       catch {file delete [gitdir PREPARE_COMMIT_MSG]}
+}
+
 proc read_diff_index {fd after} {
        global buf_rdi