git-difftool-helper.sh

   1 #!/bin/sh
   2 # git-difftool-helper is a GIT_EXTERNAL_DIFF-compatible diff tool launcher.
   3 # It supports kdiff3, kompare, tkdiff, xxdiff, meld, opendiff,
   4 # emerge, ecmerge, vimdiff, gvimdiff, and custom user-configurable tools.
   5 # This script is typically launched by using the 'git difftool'
   6 # convenience command.
   7 #
   8 # Copyright (c) 2009 David Aguilar
   9
  10 # Set GIT_DIFFTOOL_NO_PROMPT to bypass the per-file prompt.
  11 should_prompt () {
  12         test -z "$GIT_DIFFTOOL_NO_PROMPT"
  13 }
  14
  15 # This function prepares temporary files and launches the appropriate
  16 # merge tool.
  17 launch_merge_tool () {
  18         # Merged is the filename as it appears in the work tree
  19         # Local is the contents of a/filename
  20         # Remote is the contents of b/filename
  21         # Custom merge tool commands might use $BASE so we provide it
  22         MERGED="$1"
  23         LOCAL="$2"
  24         REMOTE="$3"
  25         BASE="$1"
  26
  27         # $LOCAL and $REMOTE are temporary files so prompt
  28         # the user with the real $MERGED name before launching $merge_tool.
  29         if should_prompt; then
  30                 printf "\nViewing: '$MERGED'\n"
  31                 printf "Hit return to launch '%s': " "$merge_tool"
  32                 read ans
  33         fi
  34
  35         # Run the appropriate merge tool command
  36         case "$merge_tool" in
  37         kdiff3)
  38                 basename=$(basename "$MERGED")
  39                 "$merge_tool_path" --auto \
  40                         --L1 "$basename (A)" \
  41                         --L2 "$basename (B)" \
  42                         -o "$MERGED" "$LOCAL" "$REMOTE" \
  43                         > /dev/null 2>&1
  44                 ;;
  45
  46         kompare)
  47                 "$merge_tool_path" "$LOCAL" "$REMOTE"
  48                 ;;
  49
  50         tkdiff)
  51                 "$merge_tool_path" -o "$MERGED" "$LOCAL" "$REMOTE"
  52                 ;;
  53
  54         meld)
  55                 "$merge_tool_path" "$LOCAL" "$REMOTE"
  56                 ;;
  57
  58         vimdiff)
  59                 "$merge_tool_path" -c "wincmd l" "$LOCAL" "$REMOTE"
  60                 ;;
  61
  62         gvimdiff)
  63                 "$merge_tool_path" -c "wincmd l" -f "$LOCAL" "$REMOTE"
  64                 ;;
  65
  66         xxdiff)
  67                 "$merge_tool_path" \
  68                         -X \
  69                         -R 'Accel.SaveAsMerged: "Ctrl-S"' \
  70                         -R 'Accel.Search: "Ctrl+F"' \
  71                         -R 'Accel.SearchForward: "Ctrl-G"' \
  72                         --merged-file "$MERGED" \
  73                         "$LOCAL" "$REMOTE"
  74                 ;;
  75
  76         opendiff)
  77                 "$merge_tool_path" "$LOCAL" "$REMOTE" \
  78                         -merge "$MERGED" | cat
  79                 ;;
  80
  81         ecmerge)
  82                 "$merge_tool_path" "$LOCAL" "$REMOTE" \
  83                         --default --mode=merge2 --to="$MERGED"
  84                 ;;
  85
  86         emerge)
  87                 "$merge_tool_path" -f emerge-files-command \
  88                         "$LOCAL" "$REMOTE" "$(basename "$MERGED")"
  89                 ;;
  90
  91         *)
  92                 if test -n "$merge_tool_cmd"; then
  93                         ( eval $merge_tool_cmd )
  94                 fi
  95                 ;;
  96         esac
  97 }
  98
  99 # Verifies that (difftool|mergetool).<tool>.cmd exists
 100 valid_custom_tool() {
 101         merge_tool_cmd="$(git config difftool.$1.cmd)"
 102         test -z "$merge_tool_cmd" &&
 103         merge_tool_cmd="$(git config mergetool.$1.cmd)"
 104         test -n "$merge_tool_cmd"
 105 }
 106
 107 # Verifies that the chosen merge tool is properly setup.
 108 # Built-in merge tools are always valid.
 109 valid_tool() {
 110         case "$1" in
 111         kdiff3 | kompare | tkdiff | xxdiff | meld | opendiff | emerge | vimdiff | gvimdiff | ecmerge)
 112                 ;; # happy
 113         *)
 114                 if ! valid_custom_tool "$1"
 115                 then
 116                         return 1
 117                 fi
 118                 ;;
 119         esac
 120 }
 121
 122 # Sets up the merge_tool_path variable.
 123 # This handles the difftool.<tool>.path configuration.
 124 # This also falls back to mergetool defaults.
 125 init_merge_tool_path() {
 126         merge_tool_path=$(git config difftool."$1".path)
 127         test -z "$merge_tool_path" &&
 128         merge_tool_path=$(git config mergetool."$1".path)
 129         if test -z "$merge_tool_path"; then
 130                 case "$1" in
 131                 emerge)
 132                         merge_tool_path=emacs
 133                         ;;
 134                 *)
 135                         merge_tool_path="$1"
 136                         ;;
 137                 esac
 138         fi
 139 }
 140
 141 # Allow GIT_DIFF_TOOL and GIT_MERGE_TOOL to provide default values
 142 test -n "$GIT_MERGE_TOOL" && merge_tool="$GIT_MERGE_TOOL"
 143 test -n "$GIT_DIFF_TOOL" && merge_tool="$GIT_DIFF_TOOL"
 144
 145 # If merge tool was not specified then use the diff.tool
 146 # configuration variable.  If that's invalid then reset merge_tool.
 147 # Fallback to merge.tool.
 148 if test -z "$merge_tool"; then
 149         merge_tool=$(git config diff.tool)
 150         test -z "$merge_tool" &&
 151         merge_tool=$(git config merge.tool)
 152         if test -n "$merge_tool" && ! valid_tool "$merge_tool"; then
 153                 echo >&2 "git config option diff.tool set to unknown tool: $merge_tool"
 154                 echo >&2 "Resetting to default..."
 155                 unset merge_tool
 156         fi
 157 fi
 158
 159 # Try to guess an appropriate merge tool if no tool has been set.
 160 if test -z "$merge_tool"; then
 161         # We have a $DISPLAY so try some common UNIX merge tools
 162         if test -n "$DISPLAY"; then
 163                 # If gnome then prefer meld, otherwise, prefer kdiff3 or kompare
 164                 if test -n "$GNOME_DESKTOP_SESSION_ID" ; then
 165                         merge_tool_candidates="meld kdiff3 kompare tkdiff xxdiff gvimdiff"
 166                 else
 167                         merge_tool_candidates="kdiff3 kompare tkdiff xxdiff meld gvimdiff"
 168                 fi
 169         fi
 170         if echo "${VISUAL:-$EDITOR}" | grep 'emacs' > /dev/null 2>&1; then
 171                 # $EDITOR is emacs so add emerge as a candidate
 172                 merge_tool_candidates="$merge_tool_candidates emerge opendiff vimdiff"
 173         elif echo "${VISUAL:-$EDITOR}" | grep 'vim' > /dev/null 2>&1; then
 174                 # $EDITOR is vim so add vimdiff as a candidate
 175                 merge_tool_candidates="$merge_tool_candidates vimdiff opendiff emerge"
 176         else
 177                 merge_tool_candidates="$merge_tool_candidates opendiff emerge vimdiff"
 178         fi
 179         echo "merge tool candidates: $merge_tool_candidates"
 180
 181         # Loop over each candidate and stop when a valid merge tool is found.
 182         for i in $merge_tool_candidates
 183         do
 184                 init_merge_tool_path $i
 185                 if type "$merge_tool_path" > /dev/null 2>&1; then
 186                         merge_tool=$i
 187                         break
 188                 fi
 189         done
 190
 191         if test -z "$merge_tool" ; then
 192                 echo "No known merge resolution program available."
 193                 exit 1
 194         fi
 195
 196 else
 197         # A merge tool has been set, so verify that it's valid.
 198         if ! valid_tool "$merge_tool"; then
 199                 echo >&2 "Unknown merge tool $merge_tool"
 200                 exit 1
 201         fi
 202
 203         init_merge_tool_path "$merge_tool"
 204
 205         if test -z "$merge_tool_cmd" && ! type "$merge_tool_path" > /dev/null 2>&1; then
 206                 echo "The merge tool $merge_tool is not available as '$merge_tool_path'"
 207                 exit 1
 208         fi
 209 fi
 210
 211
 212 # Launch the merge tool on each path provided by 'git diff'
 213 while test $# -gt 6
 214 do
 215         launch_merge_tool "$1" "$2" "$5"
 216         shift 7
 217 done