Mercurial > urweb
changeset 167:2be573fec9a6
Unurlifying a datatype; longjmp-based error signaling mechanism
| author | Adam Chlipala <adamc@hcoop.net> |
|---|---|
| date | Tue, 29 Jul 2008 15:25:42 -0400 |
| parents | a991431b77eb |
| children | 25b169416ea8 |
| files | include/lacweb.h include/types.h src/c/driver.c src/c/lacweb.c src/cjr_print.sml src/monoize.sml |
| diffstat | 6 files changed, 142 insertions(+), 21 deletions(-) [+] |
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--- a/include/lacweb.h Tue Jul 29 14:28:44 2008 -0400 +++ b/include/lacweb.h Tue Jul 29 15:25:42 2008 -0400 @@ -9,6 +9,13 @@ lw_context lw_init(size_t page_len, size_t heap_len); void lw_free(lw_context); void lw_reset(lw_context); +void lw_reset_keep_request(lw_context); +void lw_reset_keep_error_message(lw_context); +failure_kind lw_begin(lw_context, char *path); + +void lw_error(lw_context, failure_kind, const char *fmt, ...); +char *lw_error_message(lw_context); + void *lw_malloc(lw_context, size_t); int lw_send(lw_context, int sock);
--- a/include/types.h Tue Jul 29 14:28:44 2008 -0400 +++ b/include/types.h Tue Jul 29 15:25:42 2008 -0400 @@ -12,3 +12,6 @@ typedef lw_Basis_string lw_Basis_xhtml; typedef lw_Basis_string lw_Basis_page; + + +typedef enum { SUCCESS, FATAL, BOUNDED_RETRY, UNLIMITED_RETRY } failure_kind;
--- a/src/c/driver.c Tue Jul 29 14:28:44 2008 -0400 +++ b/src/c/driver.c Tue Jul 29 15:25:42 2008 -0400 @@ -13,8 +13,6 @@ int lw_backlog = 10; int lw_bufsize = 1024; -void lw_handle(lw_context, char*); - typedef struct node { int fd; struct node *next; @@ -51,6 +49,8 @@ static pthread_mutex_t queue_mutex = PTHREAD_MUTEX_INITIALIZER; static pthread_cond_t queue_cond = PTHREAD_COND_INITIALIZER; +#define MAX_RETRIES 5 + static void *worker(void *data) { int me = *(int *)data; lw_context ctx = lw_init(1024, 1024); @@ -68,6 +68,7 @@ printf("Handling connection with thread #%d.\n", me); while (1) { + unsigned retries_left = MAX_RETRIES; int r = recv(sock, back, lw_bufsize - (back - buf), 0); if (r < 0) { @@ -138,11 +139,58 @@ printf("Serving URI %s....\n", path); - lw_write (ctx, "HTTP/1.1 200 OK\r\n"); - lw_write(ctx, "Content-type: text/html\r\n\r\n"); - lw_write(ctx, "<html>"); - lw_handle(ctx, path); - lw_write(ctx, "</html>"); + while (1) { + failure_kind fk; + + lw_write(ctx, "HTTP/1.1 200 OK\r\n"); + lw_write(ctx, "Content-type: text/html\r\n\r\n"); + lw_write(ctx, "<html>"); + + fk = lw_begin(ctx, path); + if (fk == SUCCESS) { + lw_write(ctx, "</html>"); + break; + } else if (fk == BOUNDED_RETRY) { + if (retries_left) { + printf("Error triggers bounded retry: %s\n", lw_error_message(ctx)); + --retries_left; + } + else { + printf("Fatal error (out of retries): %s\n", lw_error_message(ctx)); + + lw_reset_keep_error_message(ctx); + lw_write(ctx, "HTTP/1.1 500 Internal Server Error\n\r"); + lw_write(ctx, "Content-type: text/plain\r\n\r\n"); + lw_write(ctx, "Fatal error (out of retries): "); + lw_write(ctx, lw_error_message(ctx)); + lw_write(ctx, "\n"); + } + } else if (fk == UNLIMITED_RETRY) + printf("Error triggers unlimited retry: %s\n", lw_error_message(ctx)); + else if (fk == FATAL) { + printf("Fatal error: %s\n", lw_error_message(ctx)); + + lw_reset_keep_error_message(ctx); + lw_write(ctx, "HTTP/1.1 500 Internal Server Error\n\r"); + lw_write(ctx, "Content-type: text/plain\r\n\r\n"); + lw_write(ctx, "Fatal error: "); + lw_write(ctx, lw_error_message(ctx)); + lw_write(ctx, "\n"); + + break; + } else { + printf("Unknown lw_handle return code!\n"); + + lw_reset_keep_request(ctx); + lw_write(ctx, "HTTP/1.1 500 Internal Server Error\n\r"); + lw_write(ctx, "Content-type: text/plain\r\n\r\n"); + lw_write(ctx, "Unknown lw_handle return code!\n"); + + break; + } + + lw_reset_keep_request(ctx); + } lw_send(ctx, sock);
--- a/src/c/lacweb.c Tue Jul 29 14:28:44 2008 -0400 +++ b/src/c/lacweb.c Tue Jul 29 15:25:42 2008 -0400 @@ -3,15 +3,24 @@ #include <string.h> #include <ctype.h> #include <assert.h> +#include <setjmp.h> +#include <stdarg.h> #include "types.h" lw_unit lw_unit_v = {}; +#define ERROR_BUF_LEN 1024 + struct lw_context { char *page, *page_front, *page_back; char *heap, *heap_front, *heap_back; char **inputs; + + jmp_buf jmp_buf; + + failure_kind failure_kind; + char error_message[ERROR_BUF_LEN]; }; extern int lw_inputs_len; @@ -27,6 +36,9 @@ ctx->inputs = calloc(lw_inputs_len, sizeof(char *)); + ctx->failure_kind = SUCCESS; + ctx->error_message[0] = 0; + return ctx; } @@ -37,12 +49,49 @@ free(ctx); } -void lw_reset(lw_context ctx) { +void lw_reset_keep_request(lw_context ctx) { ctx->page_front = ctx->page; ctx->heap_front = ctx->heap; + + ctx->failure_kind = SUCCESS; + ctx->error_message[0] = 0; +} + +void lw_reset_keep_error_message(lw_context ctx) { + ctx->page_front = ctx->page; + ctx->heap_front = ctx->heap; + + ctx->failure_kind = SUCCESS; +} + +void lw_reset(lw_context ctx) { + lw_reset_keep_request(ctx); memset(ctx->inputs, 0, lw_inputs_len * sizeof(char *)); } +void lw_handle(lw_context, char *); + +failure_kind lw_begin(lw_context ctx, char *path) { + if (!setjmp(ctx->jmp_buf)) + lw_handle(ctx, path); + + return ctx->failure_kind; +} + +void lw_error(lw_context ctx, failure_kind fk, const char *fmt, ...) { + va_list ap; + va_start(ap, fmt); + + ctx->failure_kind = fk; + vsnprintf(ctx->error_message, ERROR_BUF_LEN, fmt, ap); + + longjmp(ctx->jmp_buf, 1); +} + +char *lw_error_message(lw_context ctx) { + return ctx->error_message; +} + int lw_input_num(char*); void lw_set_input(lw_context ctx, char *name, char *value) {
--- a/src/cjr_print.sml Tue Jul 29 14:28:44 2008 -0400 +++ b/src/cjr_print.sml Tue Jul 29 15:25:42 2008 -0400 @@ -211,7 +211,7 @@ newline, string "struct", space, - string ("_lwd_" ^ x ^ "_" ^ Int.toString n), + string ("__lwd_" ^ x ^ "_" ^ Int.toString n), space, string "{", newline, @@ -451,34 +451,48 @@ fun doEm xncs = case xncs of - [] => string "Uh oh" - | (x, n, to) :: rest => - box [string "(!strcmp(request, \"", - string x, - string "\") ? ({", + [] => string ("(lw_error(ctx, FATAL, \"Error unurlifying datatype " ^ x ^ "\"), NULL)") + | (x', n, to) :: rest => + box [string "((!strncmp(request, \"", + string x', + string "\", ", + string (Int.toString (size x')), + string ") && (request[", + string (Int.toString (size x')), + string "] == 0 || request[", + string (Int.toString (size x')), + string "] == '/')) ? ({", newline, + string "struct", + space, string ("__lwd_" ^ x ^ "_" ^ Int.toString i), space, - string "__lw_tmp;", + string "*__lw_tmp = lw_malloc(ctx, sizeof(struct __lwd_", + string x, + string "_", + string (Int.toString i), + string "));", newline, - string "__lw_tmp.tag", + string "__lw_tmp->tag", space, string "=", space, - string ("__lwc_" ^ x ^ "_" ^ Int.toString n), + string ("__lwc_" ^ x' ^ "_" ^ Int.toString n), string ";", newline, string "request", space, string "+=", space, - string (Int.toString (size x)), + string (Int.toString (size x')), string ";", newline, + string "if (request[0] == '/') ++request;", + newline, case to of NONE => box [] - | SOME t => box [string "__lw_tmp.data.", - string x, + | SOME t => box [string "__lw_tmp->data.", + string x', space, string "=", space,
--- a/src/monoize.sml Tue Jul 29 14:28:44 2008 -0400 +++ b/src/monoize.sml Tue Jul 29 15:25:42 2008 -0400 @@ -115,7 +115,7 @@ | L'.TFfi ("Basis", "float") => (L'.EFfiApp ("Basis", name ^ "ifyFloat", [e]), loc) | L'.TRecord [] => (L'.EPrim (Prim.String ""), loc) - | L'.TNamed _ => (L'.EPrim (Prim.String ""), loc) + | L'.TNamed _ => (L'.EPrim (Prim.String "A"), loc) | _ => (E.errorAt loc "Don't know how to encode attribute type"; Print.eprefaces' [("Type", MonoPrint.p_typ MonoEnv.empty tAll)];