76d301f773e49fc6a314fe769f2c15049028a0ce
kent
  Tue Mar 26 14:48:39 2013 -0700
Writing some utility functions for meta files and related structures.  I debated just using existing .ra infrastructure, but decided something smaller and more specialized would be helpful.
diff --git src/hg/inc/meta.h src/hg/inc/meta.h
new file mode 100644
index 0000000..91ff185
--- /dev/null
+++ src/hg/inc/meta.h
@@ -0,0 +1,58 @@
+/* metaRa - stuff to parse and interpret a genome-hub meta.txt file, which is in 
+ * a hierarchical ra format.  That is something like:
+ *     meta topLevel
+ *     cellLine HELA
+ *
+ *         meta midLevel
+ *         target H3K4Me3
+ *         antibody abCamAntiH3k4me3
+ *       
+ *            meta lowLevel
+ *            fileName hg19/chipSeq/helaH3k4me3.narrowPeak.bigBed
+ * The file is interpreted so that lower level stanzas inherit tags from higher level ones.
+ */
+
+struct metaTagVal
+/* A tag/value pair. */
+    {
+    struct metaTagVal *next;	/* Next in list. */
+    char *tag;	/* Tag name. */
+    char *val;	/* Tag value. */
+    };
+
+struct meta
+/* A node in the metadata tree */
+    {
+    struct meta *next;  /* Pointer to next younger sibling. */
+    struct meta *children;	/* Pointer to eldest child. */
+    struct meta *parent;	/* Pointer to parent. */
+    char *name;		    /* Same as val of meta tag. Not allocated here. */
+    struct metaTagVal *tagList;	/* All tags, including the "meta" one. */
+    int indent;                 /* Indentation level. */
+    };
+
+struct meta *metaLoadAll(char *fileName, char *keyTag, char *parentTag,
+    boolean ignoreOtherStanzas, boolean ignoreIndent);
+/* Loads in all ra stanzas from file and turns them into a list of meta, some of which
+ * may have children.  The keyTag parameter is optional.  If non-null it should be set to
+ * the tag name that starts a stanza.   If null, the first tag of the first stanza will be used.
+ * The parentTag if non-NULL will be a tag name used to define the parent of a stanza.
+ * The ignoreOtherStanzas flag if set will ignore stanzas that start with other tags.  
+ * If not set the routine will abort on such stanzas.  The ignoreIndent if set will
+ * use the parentTag (which must be set) to define the hierarchy.  Otherwise the program
+ * will look at the indentation, and if there is a parentTag complain about any
+ * disagreements between indentation and parentTag. */
+
+void metaWriteAll(struct meta *metaList, char *fileName, int indent, boolean withParent);
+/* Write out metadata, including children, optionally adding meta tag.   By convention
+ * for out meta.txt/meta.ra files, indent is 3, withParent is FALSE. */
+
+char *metaLocalTagVal(struct meta *meta, char *name);
+/* Return value of tag found in this node, not going up to parents. */
+
+char *metaTagVal(struct meta *meta, char *name);
+/* Return value of tag found in this node or if its not there in parents.
+ * Returns NULL if tag not found. */
+
+struct hash *metaHash(struct meta *forest);
+/* Return hash of meta at all levels of heirarchy keyed by forest. */