git-gui: Refactor 'exec git subcmd' idiom.

As we frequently need to execute a Git subcommand and obtain
its returned output we are making heavy use of [exec git foo]
to run foo.  As I'm concerned about possibly needing to carry
environment data through a shell on Cygwin for at least some
subcommands, I'm migrating all current calls to a new git
proc.  This actually makes the code look cleaner too, as
we aren't saying 'exec git' everywhere.

Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

diff --git a/git-gui.sh b/git-gui.sh
index f5010dd47a0416eb18d823f257f4748fec621074..7ecb98b900576ed6abc8b4e4af4333a209769ba6 100755 (executable)
--- a/git-gui.sh
+++ b/git-gui.sh
@@ -46,7 +46,7 @@ proc gitdir {args} {
 proc gitexec {args} {
        global _gitexec
        if {$_gitexec eq {}} {
-               if {[catch {set _gitexec [exec git --exec-path]} err]} {
+               if {[catch {set _gitexec [git --exec-path]} err]} {
                        error "Git not installed?\n\n$err"
                }
        }
@@ -202,14 +202,14 @@ proc save_config {} {
                set value $global_config_new($name)
                if {$value ne $global_config($name)} {
                        if {$value eq $default_config($name)} {
-                               catch {exec git config --global --unset $name}
+                               catch {git config --global --unset $name}
                        } else {
                                regsub -all "\[{}\]" $value {"} value
-                               exec git config --global $name $value
+                               git config --global $name $value
                        }
                        set global_config($name) $value
                        if {$value eq $repo_config($name)} {
-                               catch {exec git config --unset $name}
+                               catch {git config --unset $name}
                                set repo_config($name) $value
                        }
                }
@@ -219,16 +219,24 @@ proc save_config {} {
                set value $repo_config_new($name)
                if {$value ne $repo_config($name)} {
                        if {$value eq $global_config($name)} {
-                               catch {exec git config --unset $name}
+                               catch {git config --unset $name}
                        } else {
                                regsub -all "\[{}\]" $value {"} value
-                               exec git config $name $value
+                               git config $name $value
                        }
                        set repo_config($name) $value
                }
        }
 }
 
+######################################################################
+##
+## handy utils
+
+proc git {args} {
+       return [eval exec git $args]
+}
+
 proc error_popup {msg} {
        set title [appname]
        if {[reponame] ne {}} {
@@ -292,7 +300,7 @@ proc ask_popup {msg} {
 ## repository setup
 
 if {   [catch {set _gitdir $env(GIT_DIR)}]
-       && [catch {set _gitdir [exec git rev-parse --git-dir]} err]} {
+       && [catch {set _gitdir [git rev-parse --git-dir]} err]} {
        catch {wm withdraw .}
        error_popup "Cannot find the git directory:\n\n$err"
        exit 1
@@ -365,7 +373,7 @@ proc repository_state {ctvar hdvar mhvar} {
 
        set mh [list]
 
-       if {[catch {set current_branch [exec git symbolic-ref HEAD]}]} {
+       if {[catch {set current_branch [git symbolic-ref HEAD]}]} {
                set current_branch {}
        } else {
                regsub ^refs/((heads|tags|remotes)/)? \
@@ -374,7 +382,7 @@ proc repository_state {ctvar hdvar mhvar} {
                        current_branch
        }
 
-       if {[catch {set hd [exec git rev-parse --verify HEAD]}]} {
+       if {[catch {set hd [git rev-parse --verify HEAD]}]} {
                set hd {}
                set ct initial
                return
@@ -402,7 +410,7 @@ proc PARENT {} {
                return $p
        }
        if {$empty_tree eq {}} {
-               set empty_tree [exec git mktree << {}]
+               set empty_tree [git mktree << {}]
        }
        return $empty_tree
 }
@@ -1042,7 +1050,7 @@ proc committer_ident {} {
        global GIT_COMMITTER_IDENT
 
        if {$GIT_COMMITTER_IDENT eq {}} {
-               if {[catch {set me [exec git var GIT_COMMITTER_IDENT]} err]} {
+               if {[catch {set me [git var GIT_COMMITTER_IDENT]} err]} {
                        error_popup "Unable to obtain your identity:\n\n$err"
                        return {}
                }
@@ -1275,7 +1283,7 @@ proc commit_committree {fd_wt curHEAD msg} {
        # -- Let rerere do its thing.
        #
        if {[file isdirectory [gitdir rr-cache]]} {
-               catch {exec git rerere}
+               catch {git rerere}
        }
 
        # -- Run the post-commit hook.
@@ -1894,7 +1902,7 @@ proc do_create_branch_action {w} {
                focus $w.desc.name_t
                return
        }
-       if {![catch {exec git show-ref --verify -- "refs/heads/$newbranch"}]} {
+       if {![catch {git show-ref --verify -- "refs/heads/$newbranch"}]} {
                tk_messageBox \
                        -icon error \
                        -type ok \
@@ -1904,7 +1912,7 @@ proc do_create_branch_action {w} {
                focus $w.desc.name_t
                return
        }
-       if {[catch {exec git check-ref-format "heads/$newbranch"}]} {
+       if {[catch {git check-ref-format "heads/$newbranch"}]} {
                tk_messageBox \
                        -icon error \
                        -type ok \
@@ -1921,7 +1929,7 @@ proc do_create_branch_action {w} {
        tracking {set rev $create_branch_trackinghead}
        expression {set rev $create_branch_revexp}
        }
-       if {[catch {set cmt [exec git rev-parse --verify "${rev}^0"]}]} {
+       if {[catch {set cmt [git rev-parse --verify "${rev}^0"]}]} {
                tk_messageBox \
                        -icon error \
                        -type ok \
@@ -2100,7 +2108,7 @@ proc do_delete_branch_action {w} {
        }
        if {$check_rev eq {:none}} {
                set check_cmt {}
-       } elseif {[catch {set check_cmt [exec git rev-parse --verify "${check_rev}^0"]}]} {
+       } elseif {[catch {set check_cmt [git rev-parse --verify "${check_rev}^0"]}]} {
                tk_messageBox \
                        -icon error \
                        -type ok \
@@ -2114,10 +2122,10 @@ proc do_delete_branch_action {w} {
        set not_merged [list]
        foreach i [$w.list.l curselection] {
                set b [$w.list.l get $i]
-               if {[catch {set o [exec git rev-parse --verify $b]}]} continue
+               if {[catch {set o [git rev-parse --verify $b]}]} continue
                if {$check_cmt ne {}} {
                        if {$b eq $check_rev} continue
-                       if {[catch {set m [exec git merge-base $o $check_cmt]}]} continue
+                       if {[catch {set m [git merge-base $o $check_cmt]}]} continue
                        if {$o ne $m} {
                                lappend not_merged $b
                                continue
@@ -2155,7 +2163,7 @@ Delete the selected branches?}
        foreach i $to_delete {
                set b [lindex $i 0]
                set o [lindex $i 1]
-               if {[catch {exec git update-ref -d "refs/heads/$b" $o} err]} {
+               if {[catch {git update-ref -d "refs/heads/$b" $o} err]} {
                        append failed " - $b: $err\n"
                } else {
                        set x [lsearch -sorted -exact $all_heads $b]
@@ -2366,7 +2374,7 @@ Staying on branch '$current_branch'."
        #    here, it Just Works(tm).  If it doesn't we are in some really ugly
        #    state that is difficult to recover from within git-gui.
        #
-       if {[catch {exec git symbolic-ref HEAD "refs/heads/$new_branch"} err]} {
+       if {[catch {git symbolic-ref HEAD "refs/heads/$new_branch"} err]} {
                error_popup "Failed to set current branch.
 
 This working directory is only partially switched.
@@ -4161,7 +4169,7 @@ proc do_quit {} {
                        set rc_geometry {}
                }
                if {$cfg_geometry ne $rc_geometry} {
-                       catch {exec git config gui.geometry $cfg_geometry}
+                       catch {git config gui.geometry $cfg_geometry}
                }
        }
 
@@ -4412,7 +4420,7 @@ $copyright" \
 
        set v {}
        append v "[appname] version $appvers\n"
-       append v "[exec git version]\n"
+       append v "[git version]\n"
        append v "\n"
        if {$tcl_patchLevel eq $tk_patchLevel} {
                append v "Tcl/Tk version $tcl_patchLevel"
@@ -5904,7 +5912,7 @@ if {[is_enabled transport]} {
 if {[is_enabled multicommit]} {
        set object_limit 2000
        if {[is_Windows]} {set object_limit 200}
-       regexp {^([0-9]+) objects,} [exec git count-objects] _junk objects_current
+       regexp {^([0-9]+) objects,} [git count-objects] _junk objects_current
        if {$objects_current >= $object_limit} {
                if {[ask_popup \
                        "This repository currently has $objects_current loose objects.