Add custom exception types

Author: iamed2

deps/error_codes.jl

@@ -0,0 +1,118 @@
+using EzXML
+using HTTP
+
+const ERROR_CODE_APPENDIX = "https://www.postgresql.org/docs/current/errcodes-appendix.html"
+
+pascalcase(str) = replace(titlecase(str), '_' => "")
+
+const BASE_CODE = """# autogenerated by deps/error_codes.jl using $ERROR_CODE_APPENDIX
+struct Class
+    chars::NTuple{2, Char}
+end
+
+Class(str::String) = Class(NTuple{2, Char}(codeunits(str)))
+
+macro c_str(str)
+    Class(str)
+end
+
+function Base.show(io::IO, c::Class)
+    print(io, "c\\\"", c.chars..., '"')
+end
+
+struct ErrorCode
+    chars::NTuple{5, Char}
+end
+
+ErrorCode(str::String) = ErrorCode(NTuple{5, Char}(codeunits(str)))
+
+macro e_str(str)
+    ErrorCode(str)
+end
+
+function Base.show(io::IO, e::ErrorCode)
+    print(io, "e\\\"", e.chars..., '"')
+end
+"""
+
+eval(Meta.parse("""
+begin
+    $BASE_CODE
+end"""))
+
+# --------------
+
+const SUCCESS_CLASS = Class("00")
+const WARNING_CLASSES = (Class("01"), Class("02"))
+const EXTERNAL_CLASSES = (Class("38"), Class("39"))
+
+error_code_html(url=ERROR_CODE_APPENDIX) = String(HTTP.get(url))
+
+function error_code_table(html)
+    parsed = parsehtml(html)
+
+    return findfirst("//table[@summary='PostgreSQL Error Codes']", parsed)
+end
+
+parse_row(node) = map(nodecontent, findall("td/code", node))
+
+function generate_error_codes(io, html=error_code_html())
+    table = error_code_table(html)
+    rows = findall("tbody/tr/td/code/../..", table)
+    id_names = Set{String}()
+
+    error_names_io = IOBuffer()
+
+    println(error_names_io, "\n\nconst ERROR_NAMES = Dict(")
+
+    print(io, BASE_CODE)
+
+    for row in rows
+        code, name = parse_row(row)
+
+        id_name = pascalcase(name)
+        class = Class(code)
+        error_code = ErrorCode(code)
+
+        if endswith(code, "000")
+            suffix = class in (SUCCESS_CLASS, WARNING_CLASSES...) ? "Class" : "ErrorClass"
+
+            println(io, "\n\nconst $(id_name)$(suffix) = PQResultError{$class}\n")
+        end
+
+        if class in WARNING_CLASSES
+            id_name *= "Warning"
+        end
+
+        if id_name in id_names
+            if class in EXTERNAL_CLASSES
+                id_name *= "Ext"  # like psycopg2
+            else
+                error("Duplicate identifier: $id_name")
+            end
+        end
+
+        push!(id_names, id_name)
+
+        println(io, "const $(id_name) = PQResultError{$class, $error_code}")
+        println(error_names_io, "    $id_name => \"$id_name\",")
+    end
+    println(error_names_io, ")")
+
+    seekstart(error_names_io)
+    write(io, error_names_io)
+
+    return
+end
+
+function main()
+    if length(ARGS) > 0
+        open(ARGS[1], "w") do fp
+            generate_error_codes(fp)
+        end
+    else
+        generate_error_codes(stdout)
+    end
+end
+
+abspath(PROGRAM_FILE) == @__FILE__() && main()

src/LibPQ.jl

@@ -79,6 +79,7 @@ const LIBPQ_CONVERSIONS = PQConversions()
 include("connections.jl")
 include("results.jl")
 include("statements.jl")
+include("exceptions.jl")
 
 include("parsing.jl")
 include("copy.jl")

src/connections.jl

@@ -93,7 +93,7 @@ returned `Connection`.
 """
 function handle_new_connection(jl_conn::Connection; throw_error::Bool=true)
     if status(jl_conn) == libpq_c.CONNECTION_BAD
-        err = error_message(jl_conn)
+        err = PQConnectionError(jl_conn)
 
         if throw_error
             close(jl_conn)
@@ -351,7 +351,10 @@ function encoding(jl_conn::Connection)
     encoding_id::Cint = libpq_c.PQclientEncoding(jl_conn.conn)
 
     if encoding_id == -1
-        error(LOGGER, "libpq could not retrieve the connection's client encoding")
+        error(LOGGER, JLConnectionError(
+            "libpq could not retrieve the connection's client encoding. " *
+            "Something is wrong with the connection."
+        ))
     end
 
     return unsafe_string(libpq_c.pg_encoding_to_char(encoding_id))
@@ -375,9 +378,9 @@ function set_encoding!(jl_conn::Connection, encoding::String)
         status = libpq_c.PQsetClientEncoding(jl_conn.conn, encoding)
 
         if status == -1
-            error(LOGGER,
+            error(LOGGER, JLConnectionError(
                 "libpq could not set the connection's client encoding to $encoding"
-            )
+            ))
         else
             jl_conn.encoding = encoding
         end
@@ -525,7 +528,7 @@ function Base.parse(::Type{ConninfoDisplay}, str::AbstractString)::ConninfoDispl
     elseif first(str) == 'D'
         Debug
     else
-        error(LOGGER, "Unexpected dispchar '$str' in PQconninfoOption")
+        error(LOGGER, JLConnectionError("Unexpected dispchar '$str' in PQconninfoOption"))
     end
 end
 
@@ -580,9 +583,13 @@ function conninfo(jl_conn::Connection)
 
     if ci_ptr == C_NULL
         if !isopen(jl_conn)
-            error(LOGGER, "Connection is closed")
+            error(LOGGER, JLConnectionError(
+                "Cannot get connection info as the connection is closed."
+            ))
         else
-            error(LOGGER, "libpq could not allocate memory for connection info")
+            error(LOGGER, JLConnectionError(
+                "libpq could not allocate memory for connection info"
+            ))
         end
     end
 
@@ -618,13 +625,15 @@ function conninfo(str::AbstractString)
     ci_ptr = libpq_c.PQconninfoParse(str, err_ref)
 
     if ci_ptr == C_NULL && err_ref[] == C_NULL
-        error(LOGGER, "libpq could not allocate memory for connection info")
+        error(LOGGER, JLConnectionError(
+            "libpq could not allocate memory for connection info"
+        ))
     end
 
     if err_ref[] != C_NULL
         err_msg = unsafe_string(err_ref[])
         libpq_c.PQfreemem(err_ref[])
-        error(err_msg)
+        error(LOGGER, ConninfoParseError(err_msg))
     end
 
     ci_array = conninfo(ci_ptr)