add self pipe, and non-block-input

1 files changed, 49 insertions, 0 deletions

diff --git a/src/util/non_block_io.cc b/src/util/non_block_io.cc
new file mode 100644
index 0000000..31edbc9
--- /dev/null
+++ b/src/util/non_block_io.cc
@@ -0,0 +1,49 @@
+#include "util/non_block_input.h"
+
+#include <unistd.h>
+#include <sys/select.h>
+
+#include "pipe.h"
+
+using namespace std;
+
+namespace ov4
+{
+
+
+/*
+ * read from both stdin, and self pipe
+ * returns immediately as soon as stdin or pipe is "readable"
+ * returns read()'s ret value
+ * and set src to the the read source (stdin or pipe)
+ */
+int non_block_read_char(char *c, int *src)
+{
+    // get fd check range
+    int max_fd;
+    if (STDIN_FILENO > self_pipe_fd[0]) max_fd = STDIN_FILENO;
+    else max_fd = self_pipe_fd[0];
+
+    // monitor STDIN, and self pipe
+    fd_set rset;
+    FD_ZERO(&rset);
+    FD_SET(STDIN_FILENO, &rset);
+    FD_SET(self_pipe_fd[0], &rset);
+
+    select(max_fd+1, &rset, nullptr, nullptr, nullptr);
+
+    int ret = -1;
+    if (FD_ISSET(self_pipe_fd[0], &rset))
+    {
+        ret = read(self_pipe_fd[0], c, 1);
+        if (src != nullptr) *src = self_pipe_fd[0];
+    }
+    else if (FD_ISSET(STDIN_FILENO, &rset))
+    {
+        ret = read(STDIN_FILENO, c, 1);
+        if (src != nullptr) *src = self_pipe_fd[0];
+    }
+    return ret;
+} 
+
+}
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