clipmenu

commit 8885306970fb0e5ef16620451b9fdd7061db2de6
parent 6edf3c437bb9bafb41e0e7383ff4def6a794cd13
Author: Chris Down <chris@chrisdown.name>
Date:   Fri,  6 Jan 2017 14:53:59 +0000

perf: Don't use date, use CRC instead

We don't need to sort by date now that we record in $cache_file, which
does it naturally for us.

Diffstat:
M
clipmenu
 | 
27
++++++---------------------
M
clipmenud
 | 
8
++++----
M
test/test-perf
 | 
8
++++----

3 files changed, 14 insertions(+), 29 deletions(-)
diff --git a/clipmenu b/clipmenu
@@ -2,35 +2,20 @@
 
 shopt -s nullglob
 
-# We use this to make sure the cache files are sorted bytewise
-export LC_COLLATE=C
-
-cache_file=/tmp/clipmenu.$USER/line_cache
+cache_dir=/tmp/clipmenu.$USER
+cache_file=$cache_dir/line_cache
 
 # It's okay to hardcode `-l 8` here as a sensible default without checking
 # whether `-l` is also in "$@", because the way that dmenu works allows a later
 # argument to override an earlier one. That is, if the user passes in `-l`, our
 # one will be ignored.
-chosen_line=$(sed 's/^[^|]\+|//' "$cache_file" | tac | uniq | dmenu -l 8 "$@")
+chosen_line=$(tac "$cache_file" | uniq | dmenu -l 8 "$@")
 
 [[ $chosen_line ]] || exit 1
 
-# Naive, but performant path, only follow expensive path if it doesn't work
-out_line=$(grep -F "|$chosen_line" "$cache_file")
-out_length=$(wc -l <<< "$out_line")
-
-if (( out_length == 1 )); then
-    # Cheap path succeded
-    file=${out_line%%|*}
-elif (( out_length > 1 )); then
-    # Cheap path failed
-    while IFS='|' read -r full_file first_line; do
-        if [[ $first_line == "$chosen_line" ]]; then
-            file=$full_file
-            break
-        fi
-    done <<< "$out_line"
-else
+file=$cache_dir/$(cksum <<< "$chosen_line")
+
+if ! [[ -f "$file" ]]; then
     # We didn't find this in cache
     printf 'FATAL: %s not in cache, run clipmenu-fsck\n' "$chosen_line" >&2
     exit 2
diff --git a/clipmenud b/clipmenud
@@ -120,17 +120,17 @@ while sleep "${CLIPMENUD_SLEEP:-0.5}"; do
             rm -- "${last_filename[$selection]}"
         fi
 
-        filename="$cache_dir/$(LC_ALL=C date +%F-%T.%N)"
 
         last_data[$selection]=$data
         last_filename[$selection]=$filename
 
+        first_line=$(get_first_line "$data")
+        filename="$cache_dir/$(cksum <<< "$first_line")"
         debug "Writing $data to $filename"
         printf '%s' "$data" > "$filename"
 
-        debug "Writing new entry to $cache_file"
-        printf '%s|%s\n' \
-            "$filename" "$(get_first_line "$data")" >> "$cache_file"
+        debug "Writing $first_line to $cache_file"
+        printf '%s\n' "$first_line" >> "$cache_file"
 
         if ! (( NO_OWN_CLIPBOARD )) && [[ $selection != primary ]]; then
             # Take ownership of the clipboard, in case the original application
diff --git a/test/test-perf b/test/test-perf
@@ -52,16 +52,16 @@ if ! (( NO_RECREATE )); then
 
         line_len=$(( (RANDOM % 10000) + 1 ))
         num_lines=$(( (RANDOM % 10) + 1 ))
-        fn=$dir/$(LC_ALL=C date +%F-%T.%N)
         data=$(
             tr -dc 'a-zA-Z0-9' < /dev/urandom |
                 fold -w "$line_len" |
                 head -"$num_lines"
         )
+        read -r first_line_raw <<< "$data"
+        printf -v first_line '%s (%s lines)\n' "$first_line_raw" "$num_lines"
+        printf '%s' "$first_line" >> "$cache_file"
+        fn=$dir/$(cksum <<< "$first_line")
         printf '%s' "$data" > "$fn"
-        read -r first_line <<< "$data"
-        printf '%s|%s (%s lines)\n' \
-            "$fn" "$first_line" "$num_lines" >> "$cache_file"
     done
 
     printf 'done\n'