[bash-completion] Support cctest/unittests, and GDB

Because why not.

No-Try: true
Bug: v8:11567
Change-Id: I763d9d0c6704f3f8c5e8336e2157336e159648fe
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2762139
Commit-Queue: Jakob Kummerow <jkummerow@chromium.org>
Auto-Submit: Jakob Kummerow <jkummerow@chromium.org>
Reviewed-by: Dan Elphick <delphick@chromium.org>
Cr-Commit-Position: refs/heads/master@{#73435}

tools/bash-completion.sh

@@ -27,39 +27,95 @@
 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 # Inspired by and based on:
-# http://src.chromium.org/viewvc/chrome/trunk/src/tools/bash-completion
+# https://chromium.googlesource.com/chromium/src/+/master/tools/bash-completion
 
 # Flag completion rule for bash.
 # To load in your shell, "source path/to/this/file".
 
 v8_source=$(readlink -f $(dirname $BASH_SOURCE)/..)
 
-_v8_flag() {
-  local cur defines targets
-  cur="${COMP_WORDS[COMP_CWORD]}"
-  defines=$(cat $v8_source/src/flags/flag-definitions.h \
+_get_v8_flags() {
+  # The first `sed` command joins lines when a line ends with '('.
+  # See http://sed.sourceforge.net/sedfaq3.html#s3.2
+  local flags_file="$v8_source/src/flags/flag-definitions.h"
+  local defines=$( \
+    sed -e :a -e '/($/N; s/(\n\s*/(/; ta' < "$flags_file" \
     | grep "^DEFINE" \
     | grep -v "DEFINE_IMPLICATION" \
     | grep -v "DEFINE_NEG_IMPLICATION" \
     | grep -v "DEFINE_VALUE_IMPLICATION" \
     | sed -e 's/_/-/g'; \
-    cat $v8_source/src/flags/flag-definitions.h \
-    | grep "^  V(harmony_" \
+    grep "^  V(harmony_" "$flags_file" \
     | sed -e 's/^  V/DEFINE-BOOL/' \
-    | sed -e 's/_/-/g' ;\
-    cat $v8_source/src/wasm/wasm-feature-flags.h \
-    | grep "^  V(" \
+    | sed -e 's/_/-/g'; \
+    grep "^  V(" $v8_source/src/wasm/wasm-feature-flags.h \
     | sed -e 's/^  V(/DEFINE-BOOL(experimental-wasm-/' \
     | sed -e 's/_/-/g')
-  targets=$(echo "$defines" \
-    | sed -ne 's/^DEFINE-[^(]*(\([^,]*\).*/--\1/p'; \
-    echo "$defines" \
-    | sed -ne 's/^DEFINE-BOOL(\([^,]*\).*/--no\1/p'; \
-    cat $v8_source/src/d8/d8.cc \
+  sed -ne 's/^DEFINE-[^(]*(\([^,]*\).*/--\1/p' <<< $defines
+  sed -ne 's/^DEFINE-BOOL(\([^,]*\).*/--no\1/p' <<< $defines
+}
+
+_get_d8_flags() {
+  cat $v8_source/src/d8/d8.cc \
     | grep "strcmp(argv\[i\]" \
-    | sed -ne 's/^[^"]*"--\([^"]*\)".*/--\1/p')
-  COMPREPLY=($(compgen -W "$targets" -- "$cur"))
+    | sed -ne 's/^[^"]*"--\([^"]*\)".*/--\1/p'
+}
+
+_d8_flag() {
+  local targets
+  targets=$(_get_v8_flags ; _get_d8_flags)
+  COMPREPLY=($(compgen -W "$targets" -- "${COMP_WORDS[COMP_CWORD]}"))
+  return 0
+}
+
+_test_flag() {
+  local targets
+  targets=$(_get_v8_flags)
+  COMPREPLY=($(compgen -W "$targets" -- "${COMP_WORDS[COMP_CWORD]}"))
   return 0
 }
 
-complete -F _v8_flag -f d8
+complete -F _d8_flag -f d8
+complete -F _test_flag -f cctest unittests
+
+# Many distros set up their own GDB completion scripts. The logic below is
+# careful to wrap any such functions (with additional logic), rather than
+# overwriting them.
+# An additional complication is that tested distros dynamically load their
+# completion scripts on first use. So in order to be able to detect their
+# presence, we have to force-load them first.
+_maybe_setup_gdb_completions() {
+  # We only want to set up the wrapping once:
+  [[ -n "$_ORIGINAL_GDB_COMPLETIONS" ]] && return 0;
+
+  # This path works for Debian, Ubuntu, and Gentoo; other distros unknown.
+  # Feel free to submit patches to extend the logic.
+  local GDB_COMP
+  for GDB_COMP in "/usr/share/bash-completion/completions/gdb"; do
+    [[ -f "$GDB_COMP" ]] && source $GDB_COMP
+  done
+  _ORIGINAL_GDB_COMPLETIONS="$(complete -p gdb 2>/dev/null \
+                               | sed -e 's/^.*-F \([^ ]*\).*/\1/')"
+
+  _gdb_v8_flag() {
+    local c i next
+    for (( i=1; i<$(($COMP_CWORD-1)); i++ )); do
+      c=${COMP_WORDS[$i]}
+      if [ "$c" = "-args" ] || [ "$c" = "--args" ] || [ "$c" == "--" ]; then
+        next=$(basename -- ${COMP_WORDS[$(($i+1))]})
+        if [ "$next" = "d8" ] ; then
+          _d8_flag
+          return 0
+        elif [ "$next" = "unittests" ] || [ "$next" = "cctest" ]; then
+          _test_flag
+          return 0
+        fi
+      fi
+    done
+    [[ -n "$_ORIGINAL_GDB_COMPLETIONS" ]] && $_ORIGINAL_GDB_COMPLETIONS
+    return 0
+  }
+  complete -F _gdb_v8_flag -f gdb
+}
+_maybe_setup_gdb_completions
+unset _maybe_setup_gdb_completions