1 files changed, 81 insertions, 0 deletions
diff --git a/src/base/piper.file.cc b/src/base/piper.file.cc
new file mode 100644
index 0000000..1443604
--- /dev/null
+++ b/src/base/piper.file.cc
@@ -0,0 +1,81 @@
+/**
+ * Copyright (c) 2023, Timothy Stack
+ *
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * * Redistributions of source code must retain the above copyright notice, this
+ * list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above copyright notice,
+ * this list of conditions and the following disclaimer in the documentation
+ * and/or other materials provided with the distribution.
+ * * Neither the name of Timothy Stack nor the names of its contributors
+ * may be used to endorse or promote products derived from this software
+ * without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ''AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "piper.file.hh"
+
+#include <arpa/inet.h>
+#include <unistd.h>
+
+#include "base/lnav_log.hh"
+#include "base/paths.hh"
+
+namespace lnav {
+namespace piper {
+
+const char HEADER_MAGIC[4] = {'L', 0, 'N', 1};
+
+const ghc::filesystem::path&
+storage_path()
+{
+    static auto INSTANCE = lnav::paths::workdir() / "piper";
+
+    return INSTANCE;
+}
+
+nonstd::optional<auto_buffer>
+read_header(int fd, const char* first8)
+{
+    if (memcmp(first8, HEADER_MAGIC, sizeof(HEADER_MAGIC)) != 0) {
+        log_trace("first 4 bytes are not a piper header: %02x%02x%02x%02x",
+                  first8[0],
+                  first8[1],
+                  first8[2],
+                  first8[3]);
+        return nonstd::nullopt;
+    }
+
+    uint32_t meta_size = ntohl(*((uint32_t*) &first8[4]));
+
+    auto meta_buf = auto_buffer::alloc(meta_size);
+    if (meta_buf.in() == nullptr) {
+        log_error("failed to alloc %d bytes for header", meta_size);
+        return nonstd::nullopt;
+    }
+    auto meta_prc = pread(fd, meta_buf.in(), meta_size, 8);
+    if (meta_prc != meta_size) {
+        log_error("failed to read piper header: %s", strerror(errno));
+        return nonstd::nullopt;
+    }
+    meta_buf.resize(meta_size);
+
+    return meta_buf;
+}
+
+}  // namespace piper
+}  // namespace lnav