block: Use an integer to count blocks

src/builtins/block.cpp

@@ -91,19 +91,17 @@ maybe_t<int> builtin_block(parser_t &parser, io_streams_t &streams, const wchar_
             return STATUS_INVALID_ARGS;
         }
 
-        if (parser.global_event_blocks.empty()) {
+        if (!parser.global_event_blocks) {
             streams.err.append_format(_(L"%ls: No blocks defined\n"), cmd);
             return STATUS_CMD_ERROR;
         }
-        parser.global_event_blocks.pop_front();
+        --parser.global_event_blocks;
         return STATUS_CMD_OK;
     }
 
     size_t block_idx = 0;
     block_t *block = parser.block_at_index(block_idx);
 
-    event_blockage_t eb = {};
-
     switch (opts.scope) {
         case LOCAL: {
             // If this is the outermost block, then we're global
@@ -128,9 +126,9 @@ maybe_t<int> builtin_block(parser_t &parser, io_streams_t &streams, const wchar_
         }
     }
     if (block) {
-        block->event_blocks.push_front(eb);
+        ++block->event_blocks;
     } else {
-        parser.global_event_blocks.push_front(eb);
+        ++parser.global_event_blocks;
     }
 
     return STATUS_CMD_OK;

src/event.cpp

@@ -173,9 +173,9 @@ static bool event_is_blocked(parser_t &parser, const event_t &e) {
     const block_t *block;
     size_t idx = 0;
     while ((block = parser.block_at_index(idx++))) {
-        if (event_block_list_blocks_type(block->event_blocks)) return true;
+        if (block->event_blocks) return true;
     }
-    return event_block_list_blocks_type(parser.global_event_blocks);
+    return parser.global_event_blocks;
 }
 
 wcstring event_get_desc(const parser_t &parser, const event_t &evt) {

src/parser.h

@@ -24,19 +24,10 @@
 #include "util.h"
 #include "wait_handle.h"
 
-struct event_t;
-class io_chain_t;
 class autoclose_fd_t;
-
-/// event_blockage_t represents a block on events.
-struct event_blockage_t {};
-
+class io_chain_t;
+struct event_t;
 struct job_group_t;
-typedef std::list<event_blockage_t> event_blockage_list_t;
-
-inline bool event_block_list_blocks_type(const event_blockage_list_t &ebls) {
-    return !ebls.empty();
-}
 
 /// Types of blocks.
 enum class block_type_t : uint8_t {
@@ -73,7 +64,7 @@ class block_t {
     wcstring function_name{};
 
     /// List of event blocks.
-    event_blockage_list_t event_blocks{};
+    uint64_t event_blocks{};
 
     // If this is a function block, the function args. Otherwise empty.
     wcstring_list_t function_args{};
@@ -329,7 +320,7 @@ class parser_t : public std::enable_shared_from_this<parser_t> {
     void assert_can_execute() const;
 
     /// Global event blocks.
-    event_blockage_list_t global_event_blocks;
+    uint64_t global_event_blocks{};
 
     /// Evaluate the expressions contained in cmd.
     ///