libupkg: Make upkg_export_find less useless.

[upkg.git] / src / libupkg.c

diff --git a/src/libupkg.c b/src/libupkg.c
index 2c0cf0724de05f358c5c1c86c09edcfc24b7accf..b87c5dde8ef0a4c444bcf8bd1c50090007811ce8 100644 (file)
--- a/src/libupkg.c
+++ b/src/libupkg.c
@@ -25,6 +25,19 @@
 
 #define MIN(a, b) ((a) < (b) ? (a) : (b))
 
+/*
+ * Print a message and execute some statement(s) if the expression evaluates
+ * to zero.  Intended to help verify that assumed constraints on the file
+ * format actually are not violated.
+ */
+#define format_assert(expr, body) do { \
+       if (!(expr)) { \
+               fprintf(stderr, "%s: %d: %s: format assertion failed: %s\n", \
+                               __FILE__, __LINE__, __func__, #expr); \
+               body; \
+       } \
+} while (0)
+
 struct upkg_name {
        unsigned long flags;
        char *name;
@@ -61,27 +74,27 @@ struct upkg_private {
 /* Default I/O operations for ordinary files. */
 static size_t file_read(void *buf, size_t size, void *handle)
 {
-       return fread(buf, 1, size, handle);
+       return fread(buf, 1, size, (FILE *)handle);
 }
 
 static int file_seek(void *handle, long offset, int whence)
 {
-       return fseek(handle, offset, whence);
+       return fseek((FILE *)handle, offset, whence);
 }
 
 static long file_tell(void *handle)
 {
-       return ftell(handle);
+       return ftell((FILE *)handle);
 }
 
 static int file_eof(void *handle)
 {
-       return feof(handle);
+       return feof((FILE *)handle);
 }
 
 static int file_close(void *handle)
 {
-       return fclose(handle);
+       return fclose((FILE *)handle);
 }
 
 const struct upkg_file_ops upkg_default_fops = {
@@ -481,13 +494,17 @@ const char *upkg_get_name(struct upkg *pkg, unsigned long idx)
        return pkg->priv->names[idx].name;
 }
 
-long upkg_export_find(struct upkg *pkg, const char *name)
+long upkg_export_find(struct upkg *pkg, long parent, const char *name)
 {
-       /* This is wrong.
-        * Export names are not necessarily unique within a package. */
-       for (unsigned i = 0; i < pkg->export_count; i++) {
-               struct upkg_export *export = &pkg->priv->exports[i];
-               if (strcmp(export->name, name) == 0) {
+       /* This only makes sense if the assertion below is not violated. */
+       long package = parent < 0 ? 0 : parent + 1;
+
+       for (unsigned long i = 0; i < pkg->export_count; i++) {
+               struct upkg_export *e = &pkg->priv->exports[i];
+
+               /* Assertion: an object's package is an export. */
+               format_assert(e->package >= 0, continue);
+               if (e->package == package && strcmp(e->name, name) == 0) {
                        return i;
                }
        }
@@ -521,11 +538,8 @@ const char *upkg_export_class(struct upkg *pkg, unsigned long idx,
 
        export = &pkg->priv->exports[idx];
 
-       /* ASSUMPTION: class references are always imports */
-       if (export->class > 0) {
-               fprintf(stderr, "Assumption Violated: class not import\n");
-               return NULL;
-       }
+       /* Assumption: class references are always imports. */
+       format_assert(export->class <= 0, return NULL);
 
        /* Get the class. */
        if (export->class == 0) {
@@ -538,17 +552,12 @@ const char *upkg_export_class(struct upkg *pkg, unsigned long idx,
                return NULL;
        iclass = &pkg->priv->imports[pkg_idx];
 
-       /* ASSUMPTION: Class references are always Core.Class */
-       if (strcmp(iclass->class_name, "Class") || strcmp(iclass->class_package, "Core")) {
-               fprintf(stderr, "Assumption Violated: class not Core.Class\n");
-               return NULL;
-       }
+       /* Assumption: class references are always Core.Class. */
+       format_assert(!strcmp(iclass->class_package, "Core"), return NULL);
+       format_assert(!strcmp(iclass->class_name, "Class"), return NULL);
 
-       /* ASSUMPTION: Package references are always imports */
-       if (iclass->package >= 0) {
-               fprintf(stderr, "Assumption Violated: package not import\n");
-               return NULL;
-       }
+       /* Assumption: package references are always imports. */
+       format_assert(iclass->package <= 0, return NULL);
 
        /* Get the package. */
        pkg_idx = -(iclass->package + 1);
@@ -556,11 +565,9 @@ const char *upkg_export_class(struct upkg *pkg, unsigned long idx,
                return NULL;
        ipackage = &pkg->priv->imports[pkg_idx];
 
-       /* ASSUMPTION: Package references are always Core.Package */
-       if (strcmp(ipackage->class_name, "Package") || strcmp(ipackage->class_package, "Core")) {
-               fprintf(stderr, "Assumption Violated: package not Core.Package\n");
-               return NULL;
-       }
+       /* Assumption: package references are always Core.Package. */
+       format_assert(!strcmp(ipackage->class_package, "Core"), return NULL);
+       format_assert(!strcmp(ipackage->class_name, "Package"), return NULL);
 
        if (package) *package = ipackage->object_name;
        return iclass->object_name;