profilers: introduce event reader module

There is no error-checking in profilers which results in raw Lua
errors being reported in cases of non-existing paths or corrupt
file structures. This patch adds a profiler-agnostic module for
event parsing, which is going to be used to introduce
user-friendly errors. It is impossible to enable it right now
because it should be included in Tarantool's build procedure
first.

Part of tarantool/tarantool#9217
Part of tarantool/tarantool#5994

Makefile.original

@@ -97,7 +97,7 @@ FILES_JITLIB= bc.lua bcsave.lua dump.lua p.lua v.lua zone.lua \
 	      dis_x86.lua dis_x64.lua dis_arm.lua dis_arm64.lua \
 	      dis_arm64be.lua dis_ppc.lua dis_mips.lua dis_mipsel.lua \
 	      dis_mips64.lua dis_mips64el.lua vmdef.lua
-FILES_UTILSLIB= avl.lua bufread.lua symtab.lua
+FILES_UTILSLIB= avl.lua bufread.lua evread.lua symtab.lua
 FILES_MEMPROFLIB= humanize.lua parse.lua process.lua
 FILES_SYSPROFLIB= parse.lua
 FILES_TOOLSLIB= memprof.lua sysprof.lua

tools/CMakeLists.txt

@@ -18,6 +18,7 @@ else()
     memprof.lua
     utils/avl.lua
     utils/bufread.lua
+    utils/evread.lua
     utils/symtab.lua
   )
   list(APPEND LUAJIT_TOOLS_DEPS tools-parse-memprof)
@@ -36,6 +37,7 @@ else()
   install(FILES
       ${CMAKE_CURRENT_SOURCE_DIR}/utils/avl.lua
       ${CMAKE_CURRENT_SOURCE_DIR}/utils/bufread.lua
+      ${CMAKE_CURRENT_SOURCE_DIR}/utils/evread.lua
       ${CMAKE_CURRENT_SOURCE_DIR}/utils/symtab.lua
     DESTINATION ${LUAJIT_DATAROOTDIR}/utils
     PERMISSIONS
@@ -65,6 +67,7 @@ else()
     sysprof.lua
     utils/avl.lua
     utils/bufread.lua
+    utils/evread.lua
     utils/symtab.lua
   )
   list(APPEND LUAJIT_TOOLS_DEPS tools-parse-sysprof)
@@ -81,6 +84,7 @@ else()
   install(FILES
       ${CMAKE_CURRENT_SOURCE_DIR}/utils/avl.lua
       ${CMAKE_CURRENT_SOURCE_DIR}/utils/bufread.lua
+      ${CMAKE_CURRENT_SOURCE_DIR}/utils/evread.lua
       ${CMAKE_CURRENT_SOURCE_DIR}/utils/symtab.lua
     DESTINATION ${LUAJIT_DATAROOTDIR}/utils
     PERMISSIONS

tools/utils/evread.lua

@@ -0,0 +1,32 @@
+local bufread = require('utils.bufread')
+local symtab = require('utils.symtab')
+
+local function make_error_handler(fmt, inputfile)
+  return function(err)
+    io.stderr:write(string.format(fmt, inputfile))
+    io.stderr:write(string.format('\n\t%s\n', err))
+    os.exit(1, true)
+  end
+end
+
+return function(parser, inputfile)
+  local _, reader = xpcall(
+    bufread.new,
+    make_error_handler('Failed to open %s.', inputfile),
+    inputfile
+  )
+
+  local _, symbols = xpcall(
+    symtab.parse,
+    make_error_handler('Failed to parse symtab from %s.', inputfile),
+    reader
+  )
+
+  local _, events = xpcall(
+    parser,
+    make_error_handler('Failed to parse profile data from %s.', inputfile),
+    reader,
+    symbols
+  )
+  return events, symbols
+end