cli: add options --offset and --limit to notmuch show

notmuch search does not output header values. However, when browsing
through a large email corpus, it can be time saving to be able to
paginate without running notmuch show for each message/thread.

Add --offset and --limit options to notmuch show. This is inspired from
commit 796b629c3b82 ("cli: add options --offset and --limit to notmuch
search").

Update man page, shell completion and add a test case to ensure it works
as expected.

Cc: Tim Culverhouse <tim@timculverhouse.com>
Cc: Tomi Ollila <tomi.ollila@iki.fi>
Signed-off-by: Robin Jarry <robin@jarry.cc>

1 files changed, 81 insertions, 0 deletions

diff --git a/test/T131-show-limiting.sh b/test/T131-show-limiting.sh
new file mode 100755
index 00000000..30d1f254
--- /dev/null
+++ b/test/T131-show-limiting.sh
@@ -0,0 +1,81 @@
+#!/usr/bin/env bash
+test_description='"notmuch show" --offset and --limit parameters'
+. $(dirname "$0")/test-lib.sh || exit 1
+
+add_email_corpus
+
+show () {
+    local kind="$1"
+    shift
+    if [ "$kind" = messages ]; then
+        set -- --unthreaded "$@"
+    fi
+    notmuch show --body=false --format=text --entire-thread=false "$@" "*" |
+        sed -nre 's/^.message\{.*\<depth:0\>.*/&/p'
+}
+
+for outp in messages threads; do
+    test_begin_subtest "$outp: limit does the right thing"
+    show $outp | head -n 20 >expected
+    show $outp --limit=20 >output
+    test_expect_equal_file expected output
+
+    test_begin_subtest "$outp: concatenation of limited shows"
+    show $outp | head -n 20 >expected
+    show $outp --limit=10 >output
+    show $outp --limit=10 --offset=10 >>output
+    test_expect_equal_file expected output
+
+    test_begin_subtest "$outp: limit larger than result set"
+    N=$(notmuch count --output=$outp "*")
+    show $outp >expected
+    show $outp --limit=$((1 + N)) >output
+    test_expect_equal_file expected output
+
+    test_begin_subtest "$outp: limit = 0"
+    test_expect_equal "$(show $outp --limit=0)" ""
+
+    test_begin_subtest "$outp: offset does the right thing"
+    # note: tail -n +N is 1-based
+    show $outp | tail -n +21 >expected
+    show $outp --offset=20 >output
+    test_expect_equal_file expected output
+
+    test_begin_subtest "$outp: offset = 0"
+    show $outp >expected
+    show $outp --offset=0 >output
+    test_expect_equal_file expected output
+
+    test_begin_subtest "$outp: negative offset"
+    show $outp | tail -n 20 >expected
+    show $outp --offset=-20 >output
+    test_expect_equal_file expected output
+
+    test_begin_subtest "$outp: negative offset"
+    show $outp | tail -n 1 >expected
+    show $outp --offset=-1 >output
+    test_expect_equal_file expected output
+
+    test_begin_subtest "$outp: negative offset combined with limit"
+    show $outp | tail -n 20 | head -n 10 >expected
+    show $outp --offset=-20 --limit=10 >output
+    test_expect_equal_file expected output
+
+    test_begin_subtest "$outp: negative offset combined with equal limit"
+    show $outp | tail -n 20 >expected
+    show $outp --offset=-20 --limit=20 >output
+    test_expect_equal_file expected output
+
+    test_begin_subtest "$outp: negative offset combined with large limit"
+    show $outp | tail -n 20 >expected
+    show $outp --offset=-20 --limit=50 >output
+    test_expect_equal_file expected output
+
+    test_begin_subtest "$outp: negative offset larger than results"
+    N=$(notmuch count --output=$outp "*")
+    show $outp >expected
+    show $outp --offset=-$((1 + N)) >output
+    test_expect_equal_file expected output
+done
+
+test_done