gitk: Refactor per-line part of getblobdiffline and its support

For later use with data sources other than a pipe, refactor the big
worker part of getblobdiffline to a separate function
parseblobdiffline.  Also refactor its initialization and wrap-up to
separate routines.

Signed-off-by: Thomas Rast <trast@inf.ethz.ch>
Signed-off-by: Paul Mackerras <paulus@samba.org>

gitk

@@ -7752,15 +7752,25 @@ proc changeworddiff {name ix op} {
     reselectline
 }
 
+proc initblobdiffvars {} {
+    global diffencoding targetline diffnparents
+    global diffinhdr currdiffsubmod diffseehere
+    set targetline {}
+    set diffnparents 0
+    set diffinhdr 0
+    set diffencoding [get_path_encoding {}]
+    set currdiffsubmod ""
+    set diffseehere -1
+}
+
 proc getblobdiffs {ids} {
     global blobdifffd diffids env
-    global diffinhdr treediffs
+    global treediffs
     global diffcontext
     global ignorespace
     global worddiff
     global limitdiffs vfilelimit curview
-    global diffencoding targetline diffnparents
+    global git_version
-    global git_version currdiffsubmod
 
     set textconv {}
     if {[package vcompare $git_version "1.6.1"] >= 0} {
@@ -7784,13 +7794,9 @@ proc getblobdiffs {ids} {
 	error_popup [mc "Error getting diffs: %s" $err]
 	return
     }
-    set targetline {}
-    set diffnparents 0
-    set diffinhdr 0
-    set diffencoding [get_path_encoding {}]
     fconfigure $bdf -blocking 0 -encoding binary -eofchar {}
     set blobdifffd($ids) $bdf
-    set currdiffsubmod ""
+    initblobdiffvars
     filerun $bdf [list getblobdiffline $bdf $diffids]
 }
 
@@ -7856,13 +7862,17 @@ proc makediffhdr {fname ids} {
     set diffline 0
 }
 
+proc blobdiffmaybeseehere {ateof} {
+    global diffseehere
+    if {$diffseehere >= 0} {
+	mark_ctext_line [lindex [split $diffseehere .] 0]
+    }
+    maybe_scroll_ctext ateof
+}
+
 proc getblobdiffline {bdf ids} {
-    global diffids blobdifffd ctext curdiffstart
+    global diffids blobdifffd
-    global diffnexthead diffnextnote difffilestart
+    global ctext
-    global ctext_file_names ctext_file_lines
-    global diffinhdr treediffs mergemax diffnparents
-    global diffencoding jump_to_here targetline diffline currdiffsubmod
-    global worddiff
 
     set nr 0
     $ctext conf -state normal
@@ -7871,6 +7881,25 @@ proc getblobdiffline {bdf ids} {
 	    catch {close $bdf}
 	    return 0
 	}
+	parseblobdiffline $ids $line
+    }
+    $ctext conf -state disabled
+    blobdiffmaybeseehere [eof $bdf]
+    if {[eof $bdf]} {
+	catch {close $bdf}
+	return 0
+    }
+    return [expr {$nr >= 1000? 2: 1}]
+}
+
+proc parseblobdiffline {ids line} {
+    global ctext curdiffstart
+    global diffnexthead diffnextnote difffilestart
+    global ctext_file_names ctext_file_lines
+    global diffinhdr treediffs mergemax diffnparents
+    global diffencoding jump_to_here targetline diffline currdiffsubmod
+    global worddiff diffseehere
+
     if {![string compare -length 5 "diff " $line]} {
 	if {![regexp {^diff (--cc|--git) } $line m type]} {
 	    set line [encoding convertfrom $line]
@@ -7908,7 +7937,7 @@ proc getblobdiffline {bdf ids} {
 	    if {!(($l & 1) && [string index $line $i] eq " " &&
 		  [string range $line 2 [expr {$i - 1}]] eq \
 		      [string range $line [expr {$i + 3}] end])} {
-		    continue
+		return
 	    }
 	    # unescape if quoted and chop off the a/ from the front
 	    if {[string index $line 0] eq "\""} {
@@ -7989,10 +8018,10 @@ proc getblobdiffline {bdf ids} {
 	    makediffhdr $fname $ids
 	} elseif {[string compare -length 3 $line "---"] == 0} {
 	    # do nothing
-		continue
+	    return
 	} elseif {[string compare -length 3 $line "+++"] == 0} {
 	    set diffinhdr 0
-		continue
+	    return
 	}
 	$ctext insert end "$line\n" filesep
 
@@ -8043,7 +8072,7 @@ proc getblobdiffline {bdf ids} {
 		}
 		if {$targetline ne {}} {
 		    if {$diffline == $targetline} {
-			    set seehere [$ctext index "end - 1 chars"]
+			set diffseehere [$ctext index "end - 1 chars"]
 			set targetline {}
 		    } else {
 			incr diffline
@@ -8066,17 +8095,6 @@ proc getblobdiffline {bdf ids} {
 	    $ctext insert end "$line\n" hunksep
 	}
     }
-    }
-    if {[info exists seehere]} {
-	mark_ctext_line [lindex [split $seehere .] 0]
-    }
-    maybe_scroll_ctext [eof $bdf]
-    $ctext conf -state disabled
-    if {[eof $bdf]} {
-	catch {close $bdf}
-	return 0
-    }
-    return [expr {$nr >= 1000? 2: 1}]
 }
 
 proc changediffdisp {} {